# ent

id: cord-001071-bjx5td52
type: WORK_OF_ART
entity:
  Using Sensor Networks to Study the Effect of Peripatetic Healthcare Workers on the Spread of Hospital Associated Infections


id: cord-102587-fugb778l
type: WORK_OF_ART
entity:
  Assessing Optimal Target Populations for Influenza Vaccination Programmes An Evidence Synthesis and Modelling Study Matrix


id: cord-260797-tc3pueow
type: WORK_OF_ART
entity:
  Robust Modeling of Human Contact Networks Across Different Scales and Proximity Sensing Techniques Contact Patterns in a High School A Comparison between Data Collected Using Wearable Sensors Contact Diaries and Friendship Surveys Data


id: cord-260039-k9rs3dql
type: CELL_LINE
entity:
  Imperial College COVID 19 Response Team 2020 and Verity et al 2020 see Table 1 5 CC BY NC ND 4 0 International license


id: cord-260039-k9rs3dql
type: ORG
entity:
  the Belgian COVID 19 Epidemic Mathematical Models of Contact Patterns Between Age Groups for Predicting the Spread of Infectious Diseases Monitoring Trends and Differences


id: cord-260039-k9rs3dql
type: ORG
entity:
  German Hospitals an Observational Study Efficient Estimation of Age Specific Social Contact Rates Between Men and Women


id: cord-141541-g5pt10yn
type: ORG
entity:
  the Clean Energy Regulator National Measurement Institute Building and Construction Commission Taxi Services Commission


id: cord-141541-g5pt10yn
type: ORG
entity:
  Mathematical Epidemiology of Infectious Diseases Model Building Analysis and Interpretation Application of SIR


id: cord-000562-ocp6yodg
type: DISEASE
entity:
  influenza A H1N1 2009 close contacts of cases were traced to provide antiviral prophylaxis within 48 h after exposure and to alert them on signs of disease


id: cord-000562-ocp6yodg
type: DISEASE
entity:
  influenza A H1N1 virus via global airline transportation Calculating the potential for withinflight transmission of influenza A H1N1


id: cord-000562-ocp6yodg
type: DISEASE
entity:
  influenza A H1N1 virus kinetics and symptom dynamics Household transmission of pandemic 2009 influenza A H1N1 virus in Osaka Contacting passengers after exposure to measles on an international flight


id: cord-307342-3gkiukh4
type: CELL_LINE
entity:
  Washington Post COVID 19 Contact Tracing We Can Live With A Roadmap and Recommendations Coronavirus recommendations ignored as case numbers rise The Washington Post A


id: cord-307342-3gkiukh4
type: GGP
entity:
  Businesses A c c e p t e d M a n u s c r i p t 12 A c c e p t e d M a n u s c r i p t A c c e p t e d M a n u s c r i p


id: cord-252903-pg0l92zb
type: ORG
entity:
  Trace Travelers for Virus Faltered When Overwhelmed Study Finds A Case for Participatory Disease Surveillance


id: cord-335518-ti889uye
type: DISEASE
entity:
  corneal inflammatory events Protocolos de higienización y seguridad en los establecimientos sanitarios de óptica y otros lugares de ejercicio professional version The Case


id: cord-248072-mlp51zgk
type: GGP
entity:
  Ngauss 25 i e σ 39 tact shape Motivated by the known homotopy between the contact line and the knot centerline


id: cord-136138-baxmoutj
type: ORG
entity:
  COVID 19 United States of Department of Health and Human Services United States National Coordination Office for Space Based Positioning Navigation and Timing Coronavirus


id: cord-136138-baxmoutj
type: WORK_OF_ART
entity:
  Guidance on the Essential Critical Infrastructure Workforce Ensuring Community and National Resilience in COVID 19 Response


id: cord-239315-dk2lwsrx
type: WORK_OF_ART
entity:
  Understanding GPS GNSS Principles and Applications LTE Advanced 3GPP Solution for IMT Advanced Smartphones


id: cord-239315-dk2lwsrx
type: LAW
entity:
  Chapter 1 Evolution of a Profession In Practical Information Security Management A Complete Guide to Planning and Implementation How


id: cord-251676-m8f6de33
type: ORG
entity:
  Assessing Disease Exposure Risk with Location Data A Proposal for Cryptographic Preservation of Privacy Contact Tracing Mobile Apps


id: cord-251676-m8f6de33
type: ORG
entity:
  Mobile Contact Tracing in Fighting Pandemic COVID 19 Issues Challenges and Solutions Cryptology ePrint Archive Development Finance Division


id: cord-251676-m8f6de33
type: WORK_OF_ART
entity:
  Experiences Challenges with Server Side WiFi Indoor Localization Using Existing Infrastructure Extracting


id: cord-314746-1o0rf0ii
type: GGP
entity:
  Parkinson s disease 63 and has shown therapeutic potential Also recent experimental results suggest that the folding kinetics of proteins


id: cord-314746-1o0rf0ii
type: WORK_OF_ART
entity:
  a Clinically Proven Protease Inhibitor Analysis of Therapeutic Targets for SARS CoV 2 and Discovery of Potential Drugs by Computational Methods Nsp3 of Coronaviruses Structures and Functions of a Large Multi


id: cord-314746-1o0rf0ii
type: ORG
entity:
  A Comprehensive Review of Current Advances in Peptide Drug Development and Design The Preferred Conformation of the Tripeptide Ala Phe Ala


id: cord-314746-1o0rf0ii
type: ORG
entity:
  the Initial Folding Intermediates of Reduced Bovine Pancreatic Trypsin Inhibitor Dominant Forces in Protein Folding Low Entropic Barrier


id: cord-314746-1o0rf0ii
type: ORG
entity:
  Suppresses the Innate Immune Response During Severe Acute Respiratory Syndrome Coronavirus Infection Mouse Hepatitis Virus Liver Pathology is Dependent


id: cord-268463-ehp0q0ry
type: DISEASE
entity:
  influenza A H5N1 virus was transmitted from live poultry to humans in Hong Kong Special Administrative Region People s


id: cord-253345-r4dhmpq1
type: ORG
entity:
  Device Free Domain Independent Gesture Recognition Micro Doppler Based Human Activity Classification Using the Mote Scale BumbleBee Radar Device


id: cord-253345-r4dhmpq1
type: ORG
entity:
  Commodity WiFi Devices Resilient Respiration Rate Monitoring With Realtime Bimodal CSI Data Cognitive Intelligence for Monitoring Fractured Post


# bib

id: cord-000562-ocp6yodg
title: Timeliness of contact tracing among flight passengers for influenza A/H1N1 2009
author: Swaan, Corien M
date: 2011-12-28
txt: ./txt/cord-000562-ocp6yodg.txt
cache: ./cache/cord-000562-ocp6yodg.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3265549/
doi: 10.1186/1471-2334-11-355
summary:
  This study evaluates the timeliness of flight-contact tracing (CT) as performed following national and international CT requests addressed to the Center of Infectious Disease Control (CIb/RIVM), and implemented by the Municipal Health Services of Schiphol Airport. In this study, we assess the time delay in contact tracing of flight passengers for influenza A/H1N1 2009 as performed in the Netherlands during the initial phase of the pandemic. For each contact investigation performed in the period April 29th until June 22nd 2009, the following data were collected: flight arrival date, first day of illness of index patient, date of laboratory diagnosis, date of contact tracing request and the date passenger lists were obtained and contact details were completed (''contacts details identified''). Our study among 17 contact investigations showed an average total delay of 3,9 days between flight arrival and identification of contacts by passenger list, which is too late for effective PEP, and late for alerting on first symptoms of disease.

abstract:
  BACKGROUND: During the initial containment phase of influenza A/H1N1 2009, close contacts of cases were traced to provide antiviral prophylaxis within 48 h after exposure and to alert them on signs of disease for early diagnosis and treatment. Passengers seated on the same row, two rows in front or behind a patient infectious for influenza, during a flight of ≥ 4 h were considered close contacts. This study evaluates the timeliness of flight-contact tracing (CT) as performed following national and international CT requests addressed to the Center of Infectious Disease Control (CIb/RIVM), and implemented by the Municipal Health Services of Schiphol Airport. METHODS: Elapsed days between date of flight arrival and the date passenger lists became available (contact details identified - CI) was used as proxy for timeliness of CT. In a retrospective study, dates of flight arrival, onset of illness, laboratory diagnosis, CT request and identification of contacts details through passenger lists, following CT requests to the RIVM for flights landed at Schiphol Airport were collected and analyzed. RESULTS: 24 requests for CT were identified. Three of these were declined as over 4 days had elapsed since flight arrival. In 17 out of 21 requests, contact details were obtained within 7 days after arrival (81%). The average delay between arrival and CI was 3,9 days (range 2-7), mainly caused by delay in diagnosis of the index patient after arrival (2,6 days). In four flights (19%), contacts were not identified or only after > 7 days. CI involving Dutch airlines was faster than non-Dutch airlines (P < 0,05). Passenger locator cards did not improve timeliness of CI. In only three flights contact details were identified within 2 days after arrival. CONCLUSION: CT for influenza A/H1N1 2009 among flight passengers was not successful for timely provision of prophylaxis. CT had little additional value for alerting passengers for disease symptoms, as this information already was provided during and after the flight. Public health authorities should take into account patient delays in seeking medical advise and laboratory confirmation in relation to maximum time to provide postexposure prophylaxis when deciding to install contact tracing measures. International standardization of CT guidelines is recommended.


id: cord-001071-bjx5td52
author: Vanhems, Philippe
date: 2013-09-11
txt: ./txt/cord-001071-bjx5td52.txt
cache: ./cache/cord-001071-bjx5td52.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3770639/
doi: 10.1371/journal.pone.0073970
summary:
  The number and duration of contacts varied between mornings, afternoons and nights, and contact matrices describing the mixing patterns between HCW and patients were built for each time period. The collected data can provide information on important aspects that impact the spreading patterns of infectious diseases, such as the strong heterogeneity of contact numbers and durations across individuals, the variability in the number of contacts during a day, and the fraction of repeated contacts across days. In particular, wearable sensors based on active Radio-Frequency IDentification (RFID) technology have been used to measure face-to-face proximity relations between individuals with a high spatio-temporal resolution in various contexts [17] that include social gatherings [18, 19] , schools [20, 21] and hospitals [22, 23] . In this paper we report on the use of wearable proximity sensors [17] to measure the numbers and durations of contacts between individuals in an acute care geriatric unit of a university hospital.

title:
  Estimating Potential Infection Transmission Routes in Hospital Wards Using Wearable Proximity Sensors

abstract:
  BACKGROUND: Contacts between patients, patients and health care workers (HCWs) and among HCWs represent one of the important routes of transmission of hospital-acquired infections (HAI). A detailed description and quantification of contacts in hospitals provides key information for HAIs epidemiology and for the design and validation of control measures. METHODS AND FINDINGS: We used wearable sensors to detect close-range interactions (“contacts”) between individuals in the geriatric unit of a university hospital. Contact events were measured with a spatial resolution of about 1.5 meters and a temporal resolution of 20 seconds. The study included 46 HCWs and 29 patients and lasted for 4 days and 4 nights. 14,037 contacts were recorded overall, 94.1% of which during daytime. The number and duration of contacts varied between mornings, afternoons and nights, and contact matrices describing the mixing patterns between HCW and patients were built for each time period. Contact patterns were qualitatively similar from one day to the next. 38% of the contacts occurred between pairs of HCWs and 6 HCWs accounted for 42% of all the contacts including at least one patient, suggesting a population of individuals who could potentially act as super-spreaders. CONCLUSIONS: Wearable sensors represent a novel tool for the measurement of contact patterns in hospitals. The collected data can provide information on important aspects that impact the spreading patterns of infectious diseases, such as the strong heterogeneity of contact numbers and durations across individuals, the variability in the number of contacts during a day, and the fraction of repeated contacts across days. This variability is however associated with a marked statistical stability of contact and mixing patterns across days. Our results highlight the need for such measurement efforts in order to correctly inform mathematical models of HAIs and use them to inform the design and evaluation of prevention strategies.


id: cord-007367-e31zhty6
title: Network position and health care worker infections
author: Tassier, Troy
date: 2015-09-07
txt: ./txt/cord-007367-e31zhty6.txt
cache: ./cache/cord-007367-e31zhty6.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7111609/
doi: 10.1007/s11403-015-0166-4
summary:
  We estimate, using an agent-based model, the effect of network position of different hospital worker groups on the spread of infectious diseases in a hospital. Following the theoretical discussion, we use our newly collected data on healthcare worker and patient contacts to model the spread of an infectious disease in a hospital setting. The model allows us to identify the healthcare worker groups that would be expected to play the largest role in the spread of infectious diseases, in terms of network position, in this hospital setting. Because of these difficulties we use a simulation approach to help us measure the average and marginal effects of individuals belonging to different worker groups in our hospital contact data. We discuss the data and use agent-based models to identify the healthcare workers whose position in the hospital contact network has the potential to create large numbers of infections in the hospital.

abstract:
  We use a newly collected data set coupled with an agent-based model to study the spread of infectious disease in hospitals. We estimate the average and marginal infections created by various worker groups in a hospital as a function of their network position in order to identify groups most crucial in a hospital-based epidemic. Surprisingly, we find that many groups with primary patient care responsibilities play a small role in spreading an infectious disease within our hospital data set. We also demonstrate that the effect of different network positions can be as important as the effect of different transmission rates for some categories of workers.


id: cord-010310-jqh75340
title: Next Generation Technology for Epidemic Prevention and Control: Data-Driven Contact Tracking
author: nan
date: 2018-12-24
txt: ./txt/cord-010310-jqh75340.txt
cache: ./cache/cord-010310-jqh75340.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7176034/
doi: 10.1109/access.2018.2882915
summary:
  Furthermore, the transmission networks of infectious diseases established using contact tracking technology can aid in the visualization of actual virus transmission paths, which enables simulations and predictions of the transmission process, assessment of the outbreak trend, and further development and deployment of more effective prevention and control strategies. Tracking the contact interactions of individuals can effectively restore the ''''invisible'''' virus transmission paths, quickly locate and isolate high-risk individuals who were in contact with infected persons, and can aid in quantitative analysis of the transmission paths, processes, and trends of the infectious diseases, all leading to the development of corresponding effective epidemic control strategies. With the aim to collect dynamic, complete, and accurate individual contact information, some researchers began to use mobile phone, wireless sensors, RFID, and GPS devices to track individual contact behaviors. Although detailed individual contact information can be collected through non-automatic methods, e.g., offline and online questionnaire, and automatic methods, e.g., mobile phone, wearable wireless sensors, RFID, and GPS devices.

abstract:
  Contact tracking is one of the key technologies in prevention and control of infectious diseases. In the face of a sudden infectious disease outbreak, contact tracking systems can help medical professionals quickly locate and isolate infected persons and high-risk individuals, preventing further spread and a large-scale outbreak of infectious disease. Furthermore, the transmission networks of infectious diseases established using contact tracking technology can aid in the visualization of actual virus transmission paths, which enables simulations and predictions of the transmission process, assessment of the outbreak trend, and further development and deployment of more effective prevention and control strategies. Exploring effective contact tracking methods will be significant. Governments, academics, and industries have all given extensive attention to this goal. In this paper, we review the developments and challenges of current contact tracing technologies regarding individual and group contact from both static and dynamic perspectives, including static individual contact tracing, dynamic individual contact tracing, static group contact tracing, and dynamic group contact tracing. With the purpose of providing useful reference and inspiration for researchers and practitioners in related fields, directions in multi-view contact tracing, multi-scale contact tracing, and AI-based contact tracing are provided for next-generation technologies for epidemic prevention and control.


id: cord-017531-fm8gl5b3
title: Scenarios: Serious, Infectious Diseases
author: Andersen, Bjørg Marit
date: 2018-09-25
txt: ./txt/cord-017531-fm8gl5b3.txt
cache: ./cache/cord-017531-fm8gl5b3.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7122114/
doi: 10.1007/978-3-319-99921-0_82
summary:
  All transport of infectious patients from the place of arrival to the hospital should take place in ambulances using the same infection control regime as for the individual infectious disease (contact infection, airborne infection, strict isolation); see isolation regimes; Chaps. • Ambulance staff and other personnel use the contact and airborne infection regime when picking up and transporting a patient. Short-time airborne isolation of exposed cases until the infection state is clarified/effect of antibacterial therapy 82.5.6 Anthrax After Staying in Turkey, Sick on the Plane Home 82.5.6.1 Patient: Strict Isolation-Air Pressure Isolate with Pressure [21, 22] Example: Two out of six people who have been on family visits in Turkey for a week, on farms with goats and skin production, are acutely ill on the plane home with cough, shortness of breath and fever. Less severe disease: isolation of index case and close contacts • Registering: All exposed persons are registered (name, address, telephone number) and followed up.

abstract:
  Scenarios for serious, infectious diseases are important procedures used to understand the special microbe’s behaviour (clinical illness, spread of infection, etc.) and how to act most rational during special dangerous outbreaks. Furthermore, scenarios describe how to handle patients, personnel and others possibly exposed to infections,- outside and inside the hospital- to stop spread of the infection as soon as possible. Today, it is not acceptable to place a patient with a known high-risk, serious infection in the same hospital room as other patients with not the same disease (WHO). In this chapter, some seldom but realistic scenario is described to better understand how to react and treat patients to stop spread of microbes during the primary phase of dangerous transmittable diseases.


id: cord-027598-76656pok
author: nan
date: 2019-01-25
txt: ./txt/cord-027598-76656pok.txt
cache: ./cache/cord-027598-76656pok.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7309220/
doi: 10.1109/access.2019.2895075
summary:
  title: A Smartphone Magnetometer-Based Diagnostic Test for Automatic Contact Tracing in Infectious Disease Epidemics This paper investigates how good a diagnostic test it would be, by evaluating the discriminative and predictive power of the smartphone magnetometer-based contact detection in multiple measures. Unfortunately, they either provide position information too coarse to be used for infectious contact detection [11] (GPS, cellular/Wi-Fi fingerprinting), require the infrastructure nearby (cellular/Wi-Fi), cannot be used indoors (GPS), consumes too much power for extended monitoring use (GPS) [12] , or could compromise privacy by exposing the identity of the device and eventually its owner (Bluetooth beacons). When the disease control authority performs an epidemiological investigation, they can use the smartphone magnetometer traces of the person confirmed infected and of the one suspected of a contact with the infected, in a system depicted in Fig. 1 .

title:
  A Smartphone Magnetometer-Based Diagnostic Test for Automatic Contact Tracing in Infectious Disease Epidemics

abstract:
  Smartphone magnetometer readings exhibit high linear correlation when two phones coexist within a short distance. Thus, the detected coexistence can serve as a proxy for close human contact events, and one can conceive using it as a possible automatic tool to modernize the contact tracing in infectious disease epidemics. This paper investigates how good a diagnostic test it would be, by evaluating the discriminative and predictive power of the smartphone magnetometer-based contact detection in multiple measures. Based on the sensitivity, specificity, likelihood ratios, and diagnostic odds ratios, we find that the decision made by the smartphone magnetometer-based test can be accurate in telling contacts from no contacts. Furthermore, through the evaluation process, we determine the appropriate range of compared trace segment sizes and the correlation cutoff values that we should use in such diagnostic tests.


id: cord-029354-c8sbqiyy
title: Can digital contact tracing make up for lost time?
author: Ivers, Louise C
date: 2020-07-16
txt: ./txt/cord-029354-c8sbqiyy.txt
cache: ./cache/cord-029354-c8sbqiyy.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7365621/
doi: 10.1016/s2468-2667(20)30160-2
abstract: nan
summary:
  Contact tracing is a fundamental public health intervention, and a mainstay in efforts to control and contain severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for the COVID-19 pandemic. 1 Regions with the most successful containment to date have approached the pandemic with integrated measures that include cohesive leadership, effective communication, physical distancing, wearing of face coverings, improvements in the built environment, promotion of hand hygiene, and support for the staff, supplies, and systems needed to care for patients-with testing and contact tracing as cornerstones of the approach. Along with efforts to expand conventional contact tracing programmes, there has been an ongoing debate about the value of digital contact tracing, ranging from issues of privacy, questions about efficacy, lower user adoption rates, and concern from some public health experts that mobile apps might distract resources from the core work of conventional contact tracing.


id: cord-031175-4dm4asen
author: Joo, Jaehun
date: 2020-09-01
txt: ./txt/cord-031175-4dm4asen.txt
cache: ./cache/cord-031175-4dm4asen.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7459240/
doi: 10.1007/s11628-020-00424-7
summary:
  Thus, for being required by both governments, Self-quarantine Safety Protection app of South Korea and Health Code app of China are representative technology for examining the relationship between the effectiveness of mandatory centralized contract tracing apps and user stress. Based on the coping theory (Beaudry and Pinsonneault 2005; Lazarus and Folkman 1984) , this study proposes a structural equation model that shows the relationships between contact tracing app users'' stress and how they accept such stress through a process called challenge appraisal. To test the research hypotheses derived from the proposed structural equation model, survey data were collected from the users of Health Code, which is the mandatory and centralized contact tracing app with the largest user base. Figure 1 shows the relationships among accuracy and privacy concerns as factors affecting stress, challenge appraisal, emotion-focused coping behavior, and infusion as a structural equations model.

title:
  Resolving the tension between full utilization of contact tracing app services and user stress as an effort to control the COVID-19 pandemic

abstract:
  Although contact tracing apps can be effective for controlling COVID-19, the app usage can be stressful for users. This study identifies countermeasures for users’ stress while maximizing full utilization of the apps. This study presents the relationships among the stress factors, users’ appraisal, users’ emotion focus coping, and the infusion to exert the full potential of the app through a structural equation model. The research model is validated by surveying Health Code app users. Given the results of the study, the contact tracing apps could become a valuable tool to control COVID-19 by removing app users’ privacy concerns.


id: cord-035285-dx5bbeqm
title: GoCoronaGo: Privacy Respecting Contact Tracing for COVID-19 Management
author: Simmhan, Yogesh
date: 2020-11-11
txt: ./txt/cord-035285-dx5bbeqm.txt
cache: ./cache/cord-035285-dx5bbeqm.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7656502/
doi: 10.1007/s41745-020-00201-5
summary:
  This proximity data of all app users are used to build a temporal contact graph, where vertices are devices, and edges indicate proximity between devices for a certain time period and with a certain Bluetooth signal strength. The use of the GCG App within an institutional setting, with data collection and usage governed by the organization, may lead to higher adoption of the app and enhance its effectiveness in contact tracing. The use of GCG is strictly voluntary, and there is an additional consent required by a user who is infected with COVID-19 before their data can be used for contact tracing-this, despite their data already being available centrally in the backend. Besides tracking Bluetooth contact data, the GCG App offers several features to inform the users about COVID-19 and engage them in preventing its spread.

abstract:
  The COVID-19 pandemic is imposing enormous global challenges in managing the spread of the virus. A key pillar to mitigation is contact tracing, which complements testing and isolation. Digital apps for contact tracing using Bluetooth technology available in smartphones have gained prevalence globally. In this article, we discuss various capabilities of such digital contact tracing, and its implication on community safety and individual privacy, among others. We further describe the GoCoronaGo institutional contact tracing app that we have developed, and the conscious and sometimes contrarian design choices we have made. We offer a detailed overview of the app, backend platform and analytics, and our early experiences with deploying the app to over 1000 users within the Indian Institute of Science campus in Bangalore. We also highlight research opportunities and open challenges for digital contact tracing and analytics over temporal networks constructed from them.


id: cord-102587-fugb778l
author: Klepac, Petra
date: 2020-02-19
txt: ./txt/cord-102587-fugb778l.txt
cache: ./cache/cord-102587-fugb778l.txt
extension: .txt
mime: text/plain
url: https://doi.org/10.1101/2020.02.16.20023754
doi: 10.1101/2020.02.16.20023754
summary:
  The amount of data collected allows us generate fine-scale age-specific population contact matrices by context (home, work, school, other) and type (conversational or physical) of contact that took place. For directly transmitted respiratory pathogens such as influenza, measles and coronaviruses, social mixing patterns shape the risk of individual-level infection [6] and population-level transmission dynamics [29, 18] , as well as the effectiveness of control measures targeted at specific age groups [2] . A landmark dataset of self-reported contacts was the POLYMOD study [22] , which collected social mixing data for 7,290 participants across eight European countries. Here we present high resolution age-specific social mixing matrices based on data from over 40,000 participants, stratified by key characteristics such as contact type and setting. Except for physical contacts, using BBC mixing matrices generally leads to more transmission in adult age-groups (particularly in ages over 25) whereas with POLYMOD dataset school-children are largely responsible for transmission regardless of how we construct the overall matrix.

title:
  Contacts in context: large-scale setting-specific social mixing matrices from the BBC Pandemic project

abstract:
  Social mixing patterns are crucial in driving transmission of infectious diseases and informing public health interventions to contain their spread. Age-specific social mixing is often inferred from surveys of self-recorded contacts which by design often have a very limited number of participants. In addition, such surveys are rare, so public health interventions are often evaluated by considering only one such study. Here we report detailed population contact patterns for United Kingdom based self-reported contact data from over 36,000 volunteers that participated in the massive citizen science project BBC Pandemic. The amount of data collected allows us generate fine-scale age-specific population contact matrices by context (home, work, school, other) and type (conversational or physical) of contact that took place. These matrices are highly relevant for informing prevention and control of new outbreaks, and evaluating strategies that reduce the amount of mixing in the population (such as school closures, social distancing, or working from home). In addition, they finally provide the possibility to use multiple sources of social mixing data to evaluate the uncertainty that stems from social mixing when designing public health interventions.


id: cord-122159-sp6o6h31
title: COVID-19 Contact-Tracing Mobile Apps: Evaluation and Assessment for Decision Makers
author: Raskar, Ramesh
date: 2020-06-04
txt: ./txt/cord-122159-sp6o6h31.txt
cache: ./cache/cord-122159-sp6o6h31.txt
extension: .txt
mime: text/plain
url: https://arxiv.org/pdf/2006.05812v1.pdf
doi: nan
summary:
  By comparing the device users'' location trails or the anonymous ID tokens they have collected with those from people who have COVID-19, one can identify others who have been near the person who is infected; this facilitates contact tracing in a more accurate and timely manner than the traditional manual approach. • An authority (public health official, healthcare provider, government official) collects the location history from the person who is infected and makes it available to users of the app. For this reason, we are building not only a contact-tracing app, but also Safe Places, a web-based tool for public health officials working to contain the COVID-19 pandemic. • Fostering trust • Developing key partnerships, including with community officials who can help drive local support for the solution • Creating solutions that meet the needs of public health officials responding to the pandemic • Focusing on the needs of the users • Providing value to the user during a contact-tracing interview even if they choose not to download the app before they have been diagnosed with COVID-19

abstract:
  A number of groups, from governments to non-profits, have quickly acted to innovate the contact-tracing process: they are designing, building, and launching contact-tracing apps in response to the COVID-19 crisis. A diverse range of approaches exist, creating challenging choices for officials looking to implement contact-tracing technology in their community and raising concerns about these choices among citizens asked to participate in contact tracing. We are frequently asked how to evaluate and differentiate between the options for contact-tracing applications. Here, we share the questions we ask about app features and plans when reviewing the many contact-tracing apps appearing on the global stage.


id: cord-125722-maclu8gh
title: Tracing Contacts to Control the COVID-19 Pandemic
author: Gunther, Christoph
date: 2020-04-01
txt: ./txt/cord-125722-maclu8gh.txt
cache: ./cache/cord-125722-maclu8gh.txt
extension: .txt
mime: text/plain
url: https://arxiv.org/pdf/2004.00517v1.pdf
doi: nan
summary:
  As a consequence tracing the contacts of people identified as carriers is essential for controlling the pandemic. • The Gesundheitsamt (trusted authority): it tests people for COVID-19 infection, it publishes an anonymized list of carriers and it facilitates the categorization of contacts. • Roaming users: their devices monitor contacts at regular intervals (30 second) and store the list of contacts my_ctc as well a a list with location and orientation information my_loc, their devices check whether there was a contact to an infected person (at least once per day), and provide support to the categorization of the contacts, potentially using location and orientation information. • Users tested positively: their devices provide their lists my_ctc as far back as their owner''s infection may have been contagious to the Gesundheitsamt, they go into treatment or at least quarantine, and cooperate in determining the category of contacts that they had.

abstract:
  The control of the COVID-19 pandemic requires a considerable reduction of contacts mostly achieved by imposing movement control up to the level of enforced quarantine. This has lead to a collapse of substantial parts of the economy. Carriers of the disease are infectious roughly 3 days after exposure to the virus. First symptoms occur later or not at all. As a consequence tracing the contacts of people identified as carriers is essential for controlling the pandemic. This tracing must work everywhere, in particular indoors, where people are closest to each other. Furthermore, it should respect people's privacy. The present paper presents a method to enable a thorough traceability with very little risk on privacy. In our opinion, the latter capabilities are necessary to control the pandemic during a future relaunch of our economy.


id: cord-136138-baxmoutj
title: Trust and Transparency in Contact Tracing Applications
author: Hobson, Stacy
date: 2020-06-19
txt: ./txt/cord-136138-baxmoutj.txt
cache: ./cache/cord-136138-baxmoutj.txt
extension: .txt
mime: text/plain
url: https://arxiv.org/pdf/2006.11356v1.pdf
doi: nan
summary:
  An example includes Contact Tracing Applications -those focused on identifying individuals who are at risk for developing COVID-19 through exposure to a person later identified as having been infected with SARS-CoV-2. The United States Centers for Disease Control and Prevention (CDC) identifies two types of digital contact tracing solutions -one focused on streamlining the capture and management of data on cases and contacts, the other on using Bluetooth or GPS to track an individuals exposure to an infected person [14] . One key benefit of contact tracing that applies to both manual efforts and digital applications is the ability to identify people who are exposed to an infected individual to encourage testing and quarantine. 3) Identifying outbreak ''hot spots'': Contact tracing solutions that capture location details in association with infections and exposures may be useful in identifying areas where 1) infections are growing, 2) the number of cases exceed a threshold, or 3) congregations of large groups of people are enabling rapid transmission.

abstract:
  The global outbreak of COVID-19 has led to focus on efforts to manage and mitigate the continued spread of the disease. One of these efforts include the use of contact tracing to identify people who are at-risk of developing the disease through exposure to an infected person. Historically, contact tracing has been primarily manual but given the exponential spread of the virus that causes COVID-19, there has been significant interest in the development and use of digital contact tracing solutions to supplement the work of human contact tracers. The collection and use of sensitive personal details by these applications has led to a number of concerns by the stakeholder groups with a vested interest in these solutions. We explore digital contact tracing solutions in detail and propose the use of a transparent reporting mechanism, FactSheets, to provide transparency of and support trust in these applications. We also provide an example FactSheet template with questions that are specific to the contact tracing application domain.


id: cord-137892-1mrsvg3b
title: Epidemic Exposure Notification with Smartwatch: A Proximity-Based Privacy-Preserving Approach
author: Ng, Pai Chet
date: 2020-07-08
txt: ./txt/cord-137892-1mrsvg3b.txt
cache: ./cache/cord-137892-1mrsvg3b.txt
extension: .txt
mime: text/plain
url: https://arxiv.org/pdf/2007.04399v1.pdf
doi: nan
summary:
  Our proximity-based privacy-preserving contact tracing (P$^3$CT) leverages the Bluetooth Low Energy (BLE) technology for reliable proximity sensing, and an ambient signature protocol for preserving identity. Proximity sensing exploits the received signal strength (RSS) to detect the user''s interaction and thus classifying them into lowor high-risk with respect to a patient diagnosed with an infectious disease. Rather than using the conventional two-way BLE communication channels (i.e., a secure channel for data exchange established through a series of pairing and handshaking processes), the smartwatch uses a non-connectable advertising channel, which was primarily used by beacon-based applications, to broadcast the packet. While it is relatively straightforward to develop such an application to the smartwatch for contact tracing purposes, it remains unclear how accurate is the proximity sensing information estimated through the RSS value and how the ambient signature information can help to prevent information leaks.

abstract:
  Businesses planning for the post-pandemic world are looking for innovative ways to protect the health and welfare of their employees and customers. Wireless technologies can play a key role in assisting contact tracing to quickly halt a local infection outbreak and prevent further spread. In this work, we present a wearable proximity and exposure notification solution based on a smartwatch that also promotes safe physical distancing in business, hospitality, or recreational facilities. Our proximity-based privacy-preserving contact tracing (P$^3$CT) leverages the Bluetooth Low Energy (BLE) technology for reliable proximity sensing, and an ambient signature protocol for preserving identity. Proximity sensing exploits the received signal strength (RSS) to detect the user's interaction and thus classifying them into low- or high-risk with respect to a patient diagnosed with an infectious disease. More precisely, a user is notified of their exposure based on their interactions, in terms of distance and time, with a patient. Our privacy-preserving protocol uses the ambient signatures to ensure that users' identities be anonymized. We demonstrate the feasibility of our proposed solution through extensive experimentation.


id: cord-141541-g5pt10yn
author: McLachlan, Scott
date: 2020-05-08
txt: ./txt/cord-141541-g5pt10yn.txt
cache: ./cache/cord-141541-g5pt10yn.txt
extension: .txt
mime: text/plain
url: https://arxiv.org/pdf/2005.06621v2.pdf
doi: nan
summary:
  Figure 3 presents the typical CTA use-case described by many authors, in which: (a) the primary CTA user and others install and register the app on their smartphones; (b) as they move around and come into close physical contact with each other, their smartphones identify other smartphones and a contact trace is recorded; (c) an upload of some information passes from the CTA on the users device, via their provider''s core network (cellular or ISP); (d) from their provider, via the internet, to the HA servers; and (e) alerts and updates can also be sent from the HA server to individuals, or every user. Some variation is observed in the literature claiming to present privacy-preserving methods regarding: (i) the type of information passed from the CTA to the health authority server; and (ii) whether the data passes directly to the HA server or, as with the Singapore (TraceTogether), Australian (COVIDSafe) and proposed Apple/Google collaboration examples, into a thirdparty supplier''s international datacentre cloud network (i.e. Google, Apple or Amazon Web Services) before being received by the HA server (Maddocks, 2020) .

title:
  Bluetooth Smartphone Apps: Are they the most private and effective solution for COVID-19 contact tracing?

abstract:
  Many digital solutions mainly involving Bluetooth technology are being proposed for Contact Tracing Apps (CTA) to reduce the spread of COVID-19. Concerns have been raised regarding privacy, consent, uptake required in a given population, and the degree to which use of CTAs can impact individual behaviours. However, very few groups have taken a holistic approach and presented a combined solution. None has presented their CTA in such a way as to ensure that even the most suggestible member of our community does not become complacent and assume that CTA operates as an invisible shield, making us and our families impenetrable or immune to the disease. We propose to build on some of the digital solutions already under development that, with addition of a Bayesian model that predicts likelihood for infection supplemented by traditional symptom and contact tracing, that can enable us to reach 90% of a population. When combined with an effective communication strategy and social distancing, we believe solutions like the one proposed here can have a very beneficial effect on containing the spread of this pandemic.


id: cord-169081-34z49l4b
title: Confidential Computing for Privacy-Preserving Contact Tracing
author: Sturzenegger, David
date: 2020-06-25
txt: ./txt/cord-169081-34z49l4b.txt
cache: ./cache/cord-169081-34z49l4b.txt
extension: .txt
mime: text/plain
url: https://arxiv.org/pdf/2006.14235v1.pdf
doi: nan
summary:
  We propose the use of the Intel SGX trusted execution environment to build a privacy-preserving contact tracing backend. While the concept of a confidential computing backend proposed in this paper can be combined with any existing contact tracing smartphone application, we describe a full contact tracing system for demonstration purposes. This paper proposes an Intel SGX-based contact tracing system which provably cannot reveal any user''s location data while providing all benefits of a traditional contact tracing system. We focus on a confidential computing backend that can be used in combination with any of the currently existing contact tracing apps, requiring only minimal modifications. Current contact tracing apps typically rely on pushing the infected user''s location data to the entire system. We propose the use of Intel SGX to build a confidential computing backend that provably cannot reveal any user data and outline a complete contact tracing system for demonstration purposes.

abstract:
  Contact tracing is paramount to fighting the pandemic but it comes with legitimate privacy concerns. This paper proposes a system enabling both, contact tracing and data privacy. We propose the use of the Intel SGX trusted execution environment to build a privacy-preserving contact tracing backend. While the concept of a confidential computing backend proposed in this paper can be combined with any existing contact tracing smartphone application, we describe a full contact tracing system for demonstration purposes. A prototype of a privacy-preserving contact tracing system based on SGX has been implemented by the authors in a hackathon.


id: cord-184854-2ledrw9j
title: Heterogeneous contact networks in COVID-19 spreading: the role of social deprivation
author: Majumdar, Arnab
date: 2020-05-01
txt: ./txt/cord-184854-2ledrw9j.txt
cache: ./cache/cord-184854-2ledrw9j.txt
extension: .txt
mime: text/plain
url: https://arxiv.org/pdf/2005.00491v1.pdf
doi: nan
summary:
  First we use theories of disease spreading on networks to look at the COVID-19 epidemic on the basis of individual contacts -these give rise to predictions which are often rather different from the homogeneous mixing approaches usually used. Newman [3] was the first to take into account that individuals needed to be resolved in terms of their ''degree distribution'', i.e. the number of people that they were in contact with, and his pioneering solutions to the disease propagation network have since been widely used [4] [5] [6] [7] for epidemics ranging from HIV to SARS-1. We demonstrate this here in the context of the city of Kolkata, which captures two aspects critical to our thesis -strong heterogeneity in terms of personal contact networks, as well as areas of great social deprivation, both of which, as will be seen, can lead to the rapid spread of epidemics.

abstract:
  We have two main aims in this paper. First we use theories of disease spreading on networks to look at the COVID-19 epidemic on the basis of individual contacts -- these give rise to predictions which are often rather different from the homogeneous mixing approaches usually used. Our second aim is to look at the role of social deprivation, again using networks as our basis, in the spread of this epidemic. We choose the city of Kolkata as a case study, but assert that the insights so obtained are applicable to a wide variety of urban environments which are densely populated and where social inequalities are rampant. Our predictions of hotspots are found to be in good agreement with those currently being identifed empirically as containment zones and provide a useful guide for identifying potential areas of concern.


id: cord-186764-qp4kq139
title: Digital Ariadne: Citizen Empowerment for Epidemic Control
author: Klopfenstein, Lorenz Cuno
date: 2020-04-16
txt: ./txt/cord-186764-qp4kq139.txt
cache: ./cache/cord-186764-qp4kq139.txt
extension: .txt
mime: text/plain
url: https://arxiv.org/pdf/2004.07717v1.pdf
doi: nan
summary:
  In this paper, we outline general requirements and design principles of personal applications for epidemic containment running on common smartphones, and we present a tool, called ''diAry'' or ''digital Ariadne'', based on voluntary location and Bluetooth tracking on personal devices, supporting a distributed query system that enables fully anonymous, privacy-preserving contact tracing. The proposed system allows individuals to keep track of movements and contacts on their own private devices and to use local traces to select relevant notifications and alerts from health authorities, thus completely eschewing, by design, any risk of surveillance. The system is composed of: a mobile application, that is voluntarily installed by users on their smartphones, keeping track of their locations through the device''s GPS sensor and interactions with other users through Bluetooth radio beacons, a privacy-aware reward system, which incentivizes app usage while collecting anonymous usage information to feed an open data set, and a distributed query system that allows recognized public authorities to selectively and anonymously notify users about possible contagion sources.

abstract:
  The COVID-19 crisis represents the most dangerous threat to public health since the H1N1 influenza pandemic of 1918. So far, the disease due to the SARS-CoV-2 virus has been countered with extreme measures at national level that attempt to suppress epidemic growth. However, these approaches require quick adoption and enforcement in order to effectively curb virus spread, and may cause unprecedented socio-economic impact. A viable alternative to mass surveillance and rule enforcement is harnessing collective intelligence by means of citizen empowerment. Mobile applications running on personal devices could significantly support this kind of approach by exploiting context/location awareness and data collection capabilities. In particular, technology-assisted location and contact tracing, if broadly adopted, may help limit the spread of infectious diseases by raising end-user awareness and enabling the adoption of selective quarantine measures. In this paper, we outline general requirements and design principles of personal applications for epidemic containment running on common smartphones, and we present a tool, called 'diAry' or 'digital Ariadne', based on voluntary location and Bluetooth tracking on personal devices, supporting a distributed query system that enables fully anonymous, privacy-preserving contact tracing. We look forward to comments, feedback, and further discussion regarding contact tracing solutions for pandemic containment.


id: cord-227492-st2ebdah
title: Apps Gone Rogue: Maintaining Personal Privacy in an Epidemic
author: Raskar, Ramesh
date: 2020-03-19
txt: ./txt/cord-227492-st2ebdah.txt
cache: ./cache/cord-227492-st2ebdah.txt
extension: .txt
mime: text/plain
url: https://arxiv.org/pdf/2003.08567v1.pdf
doi: nan
summary:
  • Users are individuals who have not been diagnosed with an infectious disease who seek to use a contact-tracing tool to better understand their exposure history and risk for disease. • Finally, we broadly speak of the government as the entity which makes location data public and informs those individuals who were likely in close contact with a diagnosed carrier, acknowledging that this responsibility is carried out by a different central actor in every continent, country or local region. The primary challenge for these technologies, as evident from their deployment in the COVID-19 crisis, remains securing the privacy of individuals, diagnosed carriers of a pathogen, and local businesses visited by diagnosed carriers, while still informing users of potential contacts. All containment strategies require analysis of diagnosed carrier location trails in order to identify other individuals at risk for infection.

abstract:
  Containment, the key strategy in quickly halting an epidemic, requires rapid identification and quarantine of the infected individuals, determination of whom they have had close contact with in the previous days and weeks, and decontamination of locations the infected individual has visited. Achieving containment demands accurate and timely collection of the infected individual's location and contact history. Traditionally, this process is labor intensive, susceptible to memory errors, and fraught with privacy concerns. With the recent almost ubiquitous availability of smart phones, many people carry a tool which can be utilized to quickly identify an infected individual's contacts during an epidemic, such as the current 2019 novel Coronavirus crisis. Unfortunately, the very same first-generation contact tracing tools have been used to expand mass surveillance, limit individual freedoms and expose the most private details about individuals. We seek to outline the different technological approaches to mobile-phone based contact-tracing to date and elaborate on the opportunities and the risks that these technologies pose to individuals and societies. We describe advanced security enhancing approaches that can mitigate these risks and describe trade-offs one must make when developing and deploying any mass contact-tracing technology. With this paper, our aim is to continue to grow the conversation regarding contact-tracing for epidemic and pandemic containment and discuss opportunities to advance this space. We invite feedback and discussion.


id: cord-238444-v9gfh3m1
title: A Smartphone enabled Approach to Manage COVID-19 Lockdown and Economic Crisis
author: Maghdid, Halgurd S.
date: 2020-04-25
txt: ./txt/cord-238444-v9gfh3m1.txt
cache: ./cache/cord-238444-v9gfh3m1.txt
extension: .txt
mime: text/plain
url: https://arxiv.org/pdf/2004.12240v2.pdf
doi: nan
summary:
  Further, authorities use case quarantine strategy and manual second/third contact-tracing to contain the COVID-19 disease. In this paper, we developed a smartphone-based approach to automatically and widely trace the contacts for confirmed COVID-19 cases. From a technical standpoint, we summarise the most important contributions of this paper as follows: 1) We build a tracking model based on positional information of registered users to conduct contact-tracing of confirmed COVID-19 cases. The best thing to do seems to be let people go out for their business, but any body tests positive of COVID-19, we would be able, through proposed framework, to trace everybody in contact with the confirmed case and managing the lockdown and mass quarantine. In this study, K-means as an unsupervised machine learning algorithm is used to cluster the users'' positions information and predict that the area should be locked down or not based on same empirical thresholds.

abstract:
  The emergence of novel COVID-19 causing an overload in health system and high mortality rate. The key priority is to contain the epidemic and prevent the infection rate. In this context, many countries are now in some degree of lockdown to ensure extreme social distancing of entire population and hence slowing down the epidemic spread. Further, authorities use case quarantine strategy and manual second/third contact-tracing to contain the COVID-19 disease. However, manual contact tracing is time consuming and labor-intensive task which tremendously overload public health systems. In this paper, we developed a smartphone-based approach to automatically and widely trace the contacts for confirmed COVID-19 cases. Particularly, contact-tracing approach creates a list of individuals in the vicinity and notifying contacts or officials of confirmed COVID-19 cases. This approach is not only providing awareness to individuals they are in the proximity to the infected area, but also tracks the incidental contacts that the COVID-19 carrier might not recall. Thereafter, we developed a dashboard to provide a plan for government officials on how lockdown/mass quarantine can be safely lifted, and hence tackling the economic crisis. The dashboard used to predict the level of lockdown area based on collected positions and distance measurements of the registered users in the vicinity. The prediction model uses K-means algorithm as an unsupervised machine learning technique for lockdown management.


id: cord-239315-dk2lwsrx
author: Magklaras, Georgios
date: 2020-05-31
txt: ./txt/cord-239315-dk2lwsrx.txt
cache: ./cache/cord-239315-dk2lwsrx.txt
extension: .txt
mime: text/plain
url: https://arxiv.org/pdf/2006.00529v1.pdf
doi: nan
summary:
  This paper discusses the aspects of data reliability and user privacy for the emerging practice of mobile phone based contact tracing for the COVID-19 pandemic. Taking Norway as an example, a country with good tradition on respecting the privacy of its citizens and among the first to launch a COVID-19 contact tracing application, it is evident that no tender processes have been disclosed for awarding public funds to construct the application [53] , calls to open source the application in order to aid the review by security experts were denied [54] and that data that contain GPS, Bluetooth LE smartphone identifiers and health status were stored in private cloud vendors [55] with unclear status on whether the data can leave the Norwegian geographic border.

title:
  A review of information security aspects of the emerging COVID-19 contact tracing mobile phone applications

abstract:
  This paper discusses the aspects of data reliability and user privacy for the emerging practice of mobile phone based contact tracing for the COVID-19 pandemic. Various countries and large technology companies have already used or plan to design and use mobile phone based solutions, in an effort to urgently expedite the process of identifying people who may have been exposed to the disease and limit its spread to the general population. However, serious concerns have been raised both in terms of the validity of the collected data as well as the extent to which implemented approaches can breach the privacy of the mobile phone users. This review examines the weaknesses of existing implementations and concludes with specific recommendations that can contribute towards increasing the safety of infrastructures that collect and process this kind of information, as well as the adoption and acceptance of these solutions from the public.


id: cord-248072-mlp51zgk
title: The shapes of physical trefoil knots
author: Johanns, Paul
date: 2020-11-06
txt: ./txt/cord-248072-mlp51zgk.txt
cache: ./cache/cord-248072-mlp51zgk.txt
extension: .txt
mime: text/plain
url: https://arxiv.org/pdf/2011.03254v2.pdf
doi: nan
summary:
  Here, we perform a compare-and-contrast investigation between the equilibrium shapes of physical real-izations of tight elastic trefoil knots and those of ideal knots based on existing purely geometric models [21, 28] , both in open and closed configurations. We realize physical knots tied onto elastomeric rods (which are straight in their unstressed configuration) in experiment complemented with fully 3D elastic simulation using the finite element method (FEM); representative examples are provided in the experimental photographs and FEMsnapshots of Fig. 1 . Our measured curvature profiles for knotted elastic filaments, both in the closed and open trefoils, are qualitatively different from those predicted by the ideal geometric models. The excellent FEM-experimental agreement confirms the observed curvature profiles and enables us to extract and map the contact pressure distribution, thereby revealing significant rod constrictions at the entrance and exit of the tight open knot.

abstract:
  We perform a compare-and-contrast investigation between the equilibrium shapes of physical and ideal trefoil knots, both in closed and open configurations. Ideal knots are purely geometric abstractions for the tightest configuration tied in a perfectly flexible, self-avoiding tube with an inextensible centerline and undeformable cross-sections. Here, we construct physical realizations of tight trefoil knots tied in an elastomeric rod, and use X-ray tomography and 3D finite element simulation for detailed characterization. Specifically, we evaluate the role of elasticity in dictating the physical knot's overall shape, self-contact regions, curvature profile, and cross-section deformation. We compare the shape of our elastic knots to prior computations of the corresponding ideal configurations. Our results on tight physical knots exhibit many similarities to their purely geometric counterparts, but also some striking dissimilarities that we examine in detail. These observations raise the hypothesis that regions of localized elastic deformation, not captured by the geometric models, could act as precursors for the weak spots that compromise the strength of knotted filaments.


id: cord-251676-m8f6de33
title: WiFiTrace: Network-based Contact Tracing for Infectious Diseases Using Passive WiFi Sensing
author: Trivedi, Amee
date: 2020-05-25
txt: ./txt/cord-251676-m8f6de33.txt
cache: ./cache/cord-251676-m8f6de33.txt
extension: .txt
mime: text/plain
url: https://arxiv.org/pdf/2005.12045v2.pdf
doi: nan
summary:
  The tool analyses WiFi logs generated by the network, and specifically association and dissociation log messages for this device, at various access points on campus to reconstruct the location(building, room numbers) visited by the user. We note that such a client-centric approach requires a user to first download a mobile app before contact tracing data can be gathered-users who have not downloaded the app (or have opted in) are not visible to other phones that are actively listening for other devices in their proximity. As discussed below, this tier uses time-evolving graphs and efficient graph algorithms to efficiently intersect trajectories of a large number of devices (typically tens of thousands of users that may be present on a university campus) to produce its report. In this section, we describe case studies that evaluate the efficacy of our contact tracing tool and also present results on the efficiency of our graph algorithms and general limitations of our WiFi sensing approach.

abstract:
  Contact tracing is a well-established and effective approach for containment of spread of infectious diseases. While bluetooth-based contact tracing method using phones have become popular recently, these approaches suffer from the need for a critical mass of adoption in order to be effective. In this paper, we present WifiTrace, a network-centric approach for contact tracing that relies on passive WiFi sensing with no client-side involvement. Our approach exploits WiFi network logs gathered by enterprise networks for performance and security monitoring and utilizes it for reconstructing device trajectories for contact tracing. Our approach is specifically designed to enhance the efficacy of traditional methods, rather than to supplant it with a new technology. We design an efficient graph algorithm to scale our approach to large networks with tens of thousands of users. We have implemented a full prototype of our system and deployed it on two large university campuses. We validate our approach and demonstrate its efficacy using case studies and detailed experiments using real-world WiFi datasets.


id: cord-252903-pg0l92zb
author: Abueg, M.
date: 2020-09-02
txt: ./txt/cord-252903-pg0l92zb.txt
cache: ./cache/cord-252903-pg0l92zb.txt
extension: .txt
mime: text/plain
url: http://medrxiv.org/cgi/content/short/2020.08.29.20184135v1?rss=1
doi: 10.1101/2020.08.29.20184135
summary:
  In this work, we use individual-based computational models to explore how digital exposure notifications can be used in conjunction with non-pharmaceutical interventions, such as traditional contact tracing and social distancing, to influence COVID-19 disease spread in a population. We use data at the county level to match the population, demographic, and occupational structure of the region, and calibrate the model with epidemiological data from Washington state and Google''s Community Mobility Reports for a time-varying infection rate ( 21 ) . Estimated total infected percentage, total deaths, and peak hospitalized under a 50% reopening scenario (an increase of 50% of the difference between pre-lockdown and post-lockdown network interactions) at various exposure notification adoption rates for King, Pierce, and Snohomish Counties, assuming no change to social distancing after the (t) β baseline and 15 manual contact tracers per 100k people.

title:
  Modeling the combined effect of digital exposure notification and non-pharmaceutical interventions on the COVID-19 epidemic in Washington state

abstract:
  Contact tracing is increasingly being used to combat COVID-19, and digital implementations are now being deployed, many of them based on Apple and Google's Exposure Notification System. These systems are new and are based on smartphone technology that has not traditionally been used for this purpose, presenting challenges in understanding possible outcomes. In this work, we use individual-based computational models to explore how digital exposure notifications can be used in conjunction with non-pharmaceutical interventions, such as traditional contact tracing and social distancing, to influence COVID-19 disease spread in a population. Specifically, we use a representative model of the household and occupational structure of three counties in the state of Washington together with a proposed digital exposure notifications deployment to quantify impacts under a range of scenarios of adoption, compliance, and mobility. In a model in which 15% of the population participated, we found that digital exposure notification systems could reduce infections and deaths by approximately 8% and 6%, effectively complementing traditional contact tracing. We believe this can serve as guidance to health authorities in Washington state and beyond on how exposure notification systems can complement traditional public health interventions to suppress the spread of COVID-19.


id: cord-253345-r4dhmpq1
title: A Systematic Review of Non-Contact Sensing for Developing a Platform to Contain COVID-19
author: Khan, Muhammad Bilal
date: 2020-09-30
txt: ./txt/cord-253345-r4dhmpq1.txt
cache: ./cache/cord-253345-r4dhmpq1.txt
extension: .txt
mime: text/plain
url: https://doi.org/10.3390/mi11100912
doi: 10.3390/mi11100912
summary:
  This study proposes a non-contact sensing platform for the early diagnosis of COVID-19 symptoms and monitoring of the human activities and health during the isolation or quarantine period. (2) Propose a non-contact sensing platform for the early diagnosis of COVID-19 symptoms and the monitoring of human activities and health during the isolation or quarantine period. The rest of paper is organized as follows: Section 2 includes a literature review of the COVID-19 pandemic, the existing non-contact wireless sensing platforms and technology exploited, the monitoring of human activities and health, and the classification approach and accuracy achieved. A non-contact sensing method uses passive Doppler radar to capture human body movements to recognize respiration and other physical activities used for monitoring health. This research presents a comprehensive review on existing non-contact sensing of human activities and health monitoring that could be used for the development of a COVID-19 pandemic platform.

abstract:
  The rapid spread of the novel coronavirus disease, COVID-19, and its resulting situation has garnered much effort to contain the virus through scientific research. The tragedy has not yet fully run its course, but it is already clear that the crisis is thoroughly global, and science is at the forefront in the fight against the virus. This includes medical professionals trying to cure the sick at risk to their own health; public health management tracking the virus and guardedly calling on such measures as social distancing to curb its spread; and researchers now engaged in the development of diagnostics, monitoring methods, treatments and vaccines. Recent advances in non-contact sensing to improve health care is the motivation of this study in order to contribute to the containment of the COVID-19 outbreak. The objective of this study is to articulate an innovative solution for early diagnosis of COVID-19 symptoms such as abnormal breathing rate, coughing and other vital health problems. To obtain an effective and feasible solution from existing platforms, this study identifies the existing methods used for human activity and health monitoring in a non-contact manner. This systematic review presents the data collection technology, data preprocessing, data preparation, features extraction, classification algorithms and performance achieved by the various non-contact sensing platforms. This study proposes a non-contact sensing platform for the early diagnosis of COVID-19 symptoms and monitoring of the human activities and health during the isolation or quarantine period. Finally, we highlight challenges in developing non-contact sensing platforms to effectively control the COVID-19 situation.


id: cord-255910-x807fpa7
author: Backer, J. A.
date: 2020-05-20
txt: ./txt/cord-255910-x807fpa7.txt
cache: ./cache/cord-255910-x807fpa7.txt
extension: .txt
mime: text/plain
url: http://medrxiv.org/cgi/content/short/2020.05.18.20101501v1?rss=1
doi: 10.1101/2020.05.18.20101501
summary:
  Contact surveys have been successfully used to quantify the reduction in the number of contacts associated with physical distancing measures in Shanghai and Wuhan, China, estimated at 88% and 86%, respectively (Zhang et al., 2020) , and in the UK (Jarvis et al., 2020) among the adult population, at 74%. By comparing the survey results before and after the implementation of these physical distancing measures, we could determine the impact on the number of contacts made in the community (i.e. outside the household), distinguishing between different age groups, genders, household sizes, days of the week and occupations. We analysed the baseline and physical distancing contact surveys by comparing the number of contacts in the community per participant stratified by several characteristics: age, gender, household size, day of the week, and occupation (as reported in the physical distancing survey, under the assumption that participants did not change occupation between the two surveys).

title:
  The impact of physical distancing measures against COVID-19 transmission on contacts and mixing patterns in the Netherlands: repeated cross-sectional surveys

abstract:
  Background During the current pandemic of coronavirus (COVID-19) many countries have taken drastic measures to reduce transmission of SARS-CoV2. The measures often include physical distancing that aims to reduce the number of contacts in the population. Little is known about the actual reduction in number of contacts as a consequence of physical distancing measures. Methods In the Netherlands, a cross-sectional survey was carried out in 2016/2017 in which 8179 participants retrospectively reported the number, age and gender of different persons they had contacted (spoken to in person or touched) during the previous day. The survey was repeated among 2830 of the original participants, using the same questionnaire, in March and April 2020 after physical distancing measures had been implemented. Results The average number of contacts in the community was reduced from on average 12.5 (interquartile range: 2-17) to 3.7 (interquartile range: 0-4) different persons per participant, a reduction of 71% (95% confidence interval: 71-71). The reduction in the number of community contacts was highest for children and adolescents (between 5 and 20 years) and smallest for elderly persons of 80 years and older. The reduction in the effective number of total contacts, measured as the largest eigenvalue of the matrix with community and household contacts, was 62% (95% confidence interval: 48 - 72). Conclusion The substantial reduction in contacts has contributed greatly in halting the COVID-19 epidemic. This reduction was unevenly distributed over age groups, household sizes and occupations. These findings offer guidance for the lifting of age-group targeted measures.


id: cord-255956-xfky1q4p
author: Narayan, Venkataraman
date: 2020-08-24
txt: ./txt/cord-255956-xfky1q4p.txt
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mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/32835358/
doi: 10.1093/jamia/ocaa184
summary:
  This case report described the innovative design and build of an algorithm that integrated available data from separate hospital-based informatics systems that perform different daily functions to augment the contact tracing process of COVID-19 patients through identifying exposed neighboring patients and healthcare workers and assess their risk. This benchmark was in line with the US-CDC Interim guidance for Risk Assessment and Management of healthcare personnel with potential exposure to COVID-19 that stated that the care team contact tracing process should be completed within 24 hours of each case''s identification. [4] Data scientists, operations managers and clinical staff worked closely to integrate data available in the informatics systems with human-based interviews to improve the timeliness, comprehensiveness and efficiency of the contact tracing process. A data-mining algorithm was developed to integrate the available data from hospital-based informatics systems that perform various day-to-day functions to augment the contact tracing process of COVID-19 patients to identify exposed HCWs and neighboring patients.

title:
  Innovative Use of Health Informatics to Augment Contact Tracing during the COVID19 Pandemic in an Acute Hospital

abstract:
  This case report described the innovative design and build of an algorithm that integrated available data from separate hospital-based informatics systems that perform different daily functions to augment the contact tracing process of COVID-19 patients through identifying exposed neighboring patients and healthcare workers and assess their risk. Prior to the establishment of the algorithm, contact tracing teams comprising six members each would spend up to 10 hours to complete contact tracing for five new COVID-19 patients. With the augmentation by the algorithm, we observed ≥60% savings in overall manhours needed for contact tracing when there were five and above daily new cases through a time-motion study and Monte-Carlo simulation. This improvement to the hospital’s contact tracing process supported more expeditious and comprehensive downstream contact tracing activities as well as improved manpower utilization in contact tracing.


id: cord-257801-rgzmpoxv
title: The Efficacy of Contact Tracing for the Containment of the 2019 Novel Coronavirus (COVID-19).
author: Keeling, Matt J
date: 2020-02-17
txt: ./txt/cord-257801-rgzmpoxv.txt
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extension: .txt
mime: text/plain
url: https://doi.org/10.1101/2020.02.14.20023036
doi: 10.1101/2020.02.14.20023036
summary:
  Using detailed survey information on social encounters coupled to predictive models, we investigate the likely efficacy of the current UK definition of a close contact (within 2 meters for 15 minutes or more) and the distribution of secondary cases that may go untraced. Using detailed survey information on social encounters coupled to predictive models, we investigate the likely efficacy of the current UK definition of a close contact (within 2 meters for 15 minutes or more) and the distribution of secondary cases that may go untraced. Using preliminary estimates of COVID-19 transmission (average latent period 4 days, average effective infectious period 1.61 days, R 0 =3.11 and assuming a simple SEIR formulation (Read et al 2020)) we compute the distribution of epidemiological, social and contact tracing characteristics across the population.

abstract:
  Contact tracing is a central public health response to infectious disease outbreaks, especially in the early stages of an outbreak when specific treatments are limited. Importation of novel Coronavirus (COVID-19) from China and elsewhere into the United Kingdom highlights the need to understand the impact of contact tracing as a control measure. Using detailed survey information on social encounters coupled to predictive models, we investigate the likely efficacy of the current UK definition of a close contact (within 2 meters for 15 minutes or more) and the distribution of secondary cases that may go untraced. Taking recent estimates for COVID-19 transmission, we show that less than 1 in 5 cases will generate any subsequent untraced cases, although this comes at a high logistical burden with an average of 36.1 individuals (95th percentiles 0-182) traced per case. Changes to the definition of a close contact can reduce this burden, but with increased risk of untraced cases; we estimate that any definition where close contact requires more than 4 hours of contact is likely to lead to uncontrolled spread.


id: cord-260039-k9rs3dql
title: Age- and Sex-Specific Modelling of the COVID-19 Epidemic
author: Doerre, A.
date: 2020-10-08
txt: ./txt/cord-260039-k9rs3dql.txt
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extension: .txt
mime: text/plain
url: http://medrxiv.org/cgi/content/short/2020.10.06.20207951v1?rss=1
doi: 10.1101/2020.10.06.20207951
summary:
  Aim: The aim of our study is to develop an ageand sex-specific model of COVID-19 transmission and to explore how contact changes effect COVID-19 infection and death rates. We develop an SEIRD-model that incorporates age-and sex-specific contacts, which shape transmission rates. The model can be used to develop scenarios which address the effects of age-and gender-specific changes in contacts due to the closing of schools, kindergarten and shops, or work in home office, as well as to explore the effect lifting of these measures. Incorporating age-and sex-specific contact rates in a COVID-19 compartment model permits exploration of the effects of changes in mitigation measures on the two genders. Our projections do not set out to forecast the actual number of COVID-19 infections in a time span of about two months, they rather assess the effect of increased contacts on the infection and mortality risks of the two genders and the various age groups.

abstract:
  Background: Recent research points towards age- and sex-specific transmission of COVID-19 infections and their outcomes. The effect of sex, however, has been overlooked in past modelling approaches of COVID-19 infections. Aim: The aim of our study is to develop an age- and sex-specific model of COVID-19 transmission and to explore how contact changes effect COVID-19 infection and death rates. Method: We consider a compartment model to establish forecasts of the COVID-19 epidemic, in which the compartments are subdivided into different age groups and genders. Estimated contact patterns, based on other studies, are incorporated to account for age- and sex-specific social behaviour. The model is fitted to real data and used for assessing hypothetical scenarios with regard to lockdown measures. Results: Under current mitigation measures as of mid-August, active COVID-19 cases will double by the end of October 2020. Infection rates will be highest among the young and working ages, but will also rise among the old. Sex ratios reveal higher infection risks among women than men at working ages; the opposite holds true at old age. Death rates in all age groups are twice as high among men as women. Small changes in contact rates at working and young ages may have a considerable effect on infections and mortality at old age, with elderly men being always at higher risk of infection and mortality. Discussion: Our results underline the high importance of the non-pharmaceutical mitigation measures in the current phase of the pandemic to prevent that an increase in contact rates leads to higher mortality among the elderly. Gender differences in contact rates, in addition to biological mechanisms related to the immune system, may contribute to sex-specific infection rates and their mortality outcome. To further explore possible pathways, more data on COVID-19 transmission is needed which includes socio-demographic information.


id: cord-260797-tc3pueow
title: Data-driven contact structures: From homogeneous mixing to multilayer networks
author: Aleta, Alberto
date: 2020-07-16
txt: ./txt/cord-260797-tc3pueow.txt
cache: ./cache/cord-260797-tc3pueow.txt
extension: .txt
mime: text/plain
url: https://doi.org/10.1371/journal.pcbi.1008035
doi: 10.1371/journal.pcbi.1008035
summary:
  In addition, we conduct extensive numerical simulations and conclude that heterogeneities in the contact network are important for a proper determination of the epidemic threshold, whereas the age-structure plays a bigger role beyond the onset of the outbreak. To bridge this gap, in this paper, we focus on analyzing the role that disease-independent heterogeneity in host contact rates plays in the spreading of epidemics in large populations under several scenarios, both numerically and analytically. A slightly better approximation is to divide the population into agegroups, given the demographic structure of the population, Fig 1B, and establish a different number of contacts between and within them (model M), which is the common approach currently used in the epidemic literature to model age-mixing patterns. Nevertheless, most network approaches focus only on determining the role that the difference in the number of contacts of the population has on the impact of disease dynamics but ignore other types of heterogeneities such as the age mixing patterns.

abstract:
  The modeling of the spreading of communicable diseases has experienced significant advances in the last two decades or so. This has been possible due to the proliferation of data and the development of new methods to gather, mine and analyze it. A key role has also been played by the latest advances in new disciplines like network science. Nonetheless, current models still lack a faithful representation of all possible heterogeneities and features that can be extracted from data. Here, we bridge a current gap in the mathematical modeling of infectious diseases and develop a framework that allows to account simultaneously for both the connectivity of individuals and the age-structure of the population. We compare different scenarios, namely, i) the homogeneous mixing setting, ii) one in which only the social mixing is taken into account, iii) a setting that considers the connectivity of individuals alone, and finally, iv) a multilayer representation in which both the social mixing and the number of contacts are included in the model. We analytically show that the thresholds obtained for these four scenarios are different. In addition, we conduct extensive numerical simulations and conclude that heterogeneities in the contact network are important for a proper determination of the epidemic threshold, whereas the age-structure plays a bigger role beyond the onset of the outbreak. Altogether, when it comes to evaluate interventions such as vaccination, both sources of individual heterogeneity are important and should be concurrently considered. Our results also provide an indication of the errors incurred in situations in which one cannot access all needed information in terms of connectivity and age of the population.


id: cord-263455-dquztf5l
author: Schoenmakers, Anne
date: 2020-10-15
txt: ./txt/cord-263455-dquztf5l.txt
cache: ./cache/cord-263455-dquztf5l.txt
extension: .txt
mime: text/plain
url: https://doi.org/10.2147/rrtm.s190300
doi: 10.2147/rrtm.s190300
summary:
  More chemoprophylaxis research is needed on: enhanced medication regimens; interventions in varying (epidemiological) settings, including focal mass drug administration (fMDA); specific approaches per contact type; combinations with screening variations and field-friendly rapid tests, if available in the future; community and health staff education; ongoing antibiotic resistance surveillance; and administering chemoprophylaxis with SDR-PEP prior to BCG administration. But, given the evidence for the effectiveness of SDR-PEP and the WHO guidelines for its use, the ethics of testing new post-exposure immunoprophylactic approaches for leprosy prevention without combining them with chemoprophylaxis in both the intervention and control group needs to be discussed. The combined effect of chemoprophylaxis with single dose rifampicin and immunoprophylaxis with BCG to prevent leprosy in contacts of newly diagnosed leprosy cases: a cluster randomized controlled trial (MALTALEP study)

title:
  The State of Affairs in Post-Exposure Leprosy Prevention: A Descriptive Meta-Analysis on Immuno- and Chemo-Prophylaxis

abstract:
  OBJECTIVE: Annually, over 200,000 people are diagnosed with leprosy, also called Hansen’s disease. This number has been relatively stable over the past years. Progress has been made in the fields of chemoprophylaxis and immunoprophylaxis to prevent leprosy, with a primary focus on close contacts of patients. In this descriptive meta-analysis, we summarize the evidence and identify knowledge gaps regarding post-exposure prophylaxis against leprosy. METHODS: A systematic literature search according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology was conducted by searching the medical scientific databases Cochrane, Embase, Pubmed/MEDLINE, Research Gate, Scopus and Web of Science on Jan. 22, 2020, using a combination of synonyms for index terms in four languages: “leprosy” and “population” or “contacts” and “prevention” or “prophylaxis.” Subsequently, Infolep.org and Google Scholar were searched and the "snowball method" was used to retrieve other potentially relevant literature. The found articles were screened for eligibility using predetermined inclusion and exclusion criteria. RESULTS: After deduplication, 1,515 articles were screened, and 125 articles were included in this descriptive meta-analysis. Immunoprophylaxis by bacillus Calmette-Guérin (BCG) vaccination is known to provide protection against leprosy. The protection it offers is higher in household contacts of leprosy patients compared with the general population and is seen to decline over time. Contact follow-up screening is important in the first period after BCG administration, as a substantial number of new leprosy patients presents three months post-vaccination. Evidence for the benefit of re-vaccination is conflicting. The World Health Organization (WHO) included BCG in its Guidelines for the Diagnosis, Treatment and Prevention of Leprosy by stating that BCG at birth should be maintained in at least all leprosy high-burden regions. Literature shows that several vaccination interventions with other immunoprophylactic agents demonstrate similar or slightly less efficacy in leprosy risk reduction compared with BCG. However, most of these studies do not exclusively focus on post-exposure prophylaxis. Two vaccines are considered future candidates for leprosy prophylaxis: Mycobacterium indicus pranii (MiP) and LepVax. For chemoprophylaxis, trials were performed with dapsone/acedapsone, rifampicin, and ROM, a combination of rifampicin, ofloxacin, and minocycline. Single-dose rifampicin is favored as post-exposure prophylaxis, abbreviated as SDR-PEP. It demonstrated a protective effect of 57% in the first two years after administration to contacts of leprosy patients. It is inexpensive, and adverse events are rare. The risk of SDR-PEP inducing rifampicin resistance is considered negligible, but continuous monitoring in accordance with WHO policies should be encouraged. The integration of contact screening and SDR-PEP administration into different leprosy control programs was found to be feasible and well accepted. Since 2018, SDR-PEP is included in the WHO Guidelines for the Diagnosis, Treatment and Prevention of Leprosy. CONCLUSION: Progress has been made in the areas of chemoprophylaxis and immunoprophylaxis to prevent leprosy in contacts of patients. Investing in vaccine studies, like LepVax and MiP, and increasing harmonization between tuberculosis (TB) and leprosy research groups is important. SDR-PEP is promising as a chemoprophylactic agent, and further implementation should be promoted. More chemoprophylaxis research is needed on: enhanced medication regimens; interventions in varying (epidemiological) settings, including focal mass drug administration (fMDA); specific approaches per contact type; combinations with screening variations and field-friendly rapid tests, if available in the future; community and health staff education; ongoing antibiotic resistance surveillance; and administering chemoprophylaxis with SDR-PEP prior to BCG administration. Additionally, both leprosy prophylactic drug registration nationally and prophylactic drug availability globally at low or no cost are important for the implementation and further upscaling of preventive measures against leprosy, such as SDR-PEP and new vaccines.


id: cord-265891-jmpterrj
title: Cost–benefit of limited isolation and testing in COVID-19 mitigation
author: Eilersen, Andreas
date: 2020-10-29
txt: ./txt/cord-265891-jmpterrj.txt
cache: ./cache/cord-265891-jmpterrj.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/33122753/
doi: 10.1038/s41598-020-75640-2
summary:
  Therefore, we will here implement a crude form of contact tracing where we (1) close the workplaces of people who are tested positive for the disease, (2) isolate their regular social contacts for a limited period, and (3) keep symptomatic individuals in quarantine until they recover. If 10% efficiency is possible, corresponding to detecting about a third of infectious cases, then peak height could be reduced by a factor of almost three with to a 60% drop, if the probability of infected people being tested is only 10% per day of illness. In Fig. 4 , we show two possible scenarios where testing and contact tracing is implemented after a 30-day lockdown with a 75% reduction of the work and social spheres. Using reasonable COVID-19 infection parameters we find that the 1STQ strategy can contribute to epidemic mitigation, in the sense that it can reduce the peak number of infected individuals by about a factor of two even with a realistic testing rate of 10% per day of illness.

abstract:
  The international community has been put in an unprecedented situation by the COVID-19 pandemic. Creating models to describe and quantify alternative mitigation strategies becomes increasingly urgent. In this study, we propose an agent-based model of disease transmission in a society divided into closely connected families, workplaces, and social groups. This allows us to discuss mitigation strategies, including targeted quarantine measures. We find that workplace and more diffuse social contacts are roughly equally important to disease spread, and that an effective lockdown must target both. We examine the cost–benefit of replacing a lockdown with tracing and quarantining contacts of the infected. Quarantine can contribute substantially to mitigation, even if it has short duration and is done within households. When reopening society, testing and quarantining is a strategy that is much cheaper in terms of lost workdays than a long lockdown. A targeted quarantine strategy is quite efficient with only 5 days of quarantine, and its effect increases when testing is more widespread.


id: cord-266878-z7qn80tw
title: COVID 19—An eye on the virus
author: Cho, Pauline
date: 2020-05-31
txt: ./txt/cord-266878-z7qn80tw.txt
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mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/32507407/
doi: 10.1016/j.clae.2020.05.011
abstract: nan
summary:
  Regarding the use of contact lenses during this period of worldwide infection, mixed messages have emerged from various health sources, making it difficult for practitioners to provide absolute guidance to their patients. In addition, contact lens wearers may experience minor discomfort or irritation more frequently than spectacle wearers [14] , and this in turn increases the chance of the natural response to touch or rub eyes [15] . Practitioners of course, are responsible for impressing upon their patients the importance of good hygiene, but some additional precautions are needed during this time of pandemic. As patients may be unable to visit clinics or practices due to lockdown, it may be advisable for practitioners to contact the parents of all of their orthokeratology patients to alert them about this problem. The COVID-19 pandemic: Important considerations for contact lens practitioners


id: cord-268126-u9z1rir1
author: Ranisch, Robert
date: 2020-10-21
txt: ./txt/cord-268126-u9z1rir1.txt
cache: ./cache/cord-268126-u9z1rir1.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/33106749/
doi: 10.1007/s10676-020-09566-8
summary:
  The viability of CT apps as a useful pandemic-response measure, depends on a complex interplay of criteria, such as pragmatic assumptions about effectiveness, the likelihood of public health benefit, technological specifications, legal requirements etc. Nevertheless, risks that cannot be easily mitigated or avoided could still be acceptable, considering the severity of a pandemic situation, the importance of effective contact tracing to manage it, and the scope of established measures to stop virus transmission. Predicting future uptake of CT apps is difficult and depends on various factors, such as the penetration range rate of digital technologies in a society, the possibility to download and use the app on different types of smartphones, the credibility of institutions offering these solutions, and viable solutions for ethical concerns such as data security. Ethical considerations to guide the use of digital proximity tracking technologies for COVID-19 contact tracing.

title:
  Digital contact tracing and exposure notification: ethical guidance for trustworthy pandemic management

abstract:
  There is growing interest in contact tracing apps (CT apps) for pandemic management. It is crucial to consider ethical requirements before, while, and after implementing such apps. In this paper, we illustrate the complexity and multiplicity of the ethical considerations by presenting an ethical framework for a responsible design and implementation of CT apps. Using this framework as a starting point, we briefly highlight the interconnection of social and political contexts, available measures of pandemic management, and a multi-layer assessment of CT apps. We will discuss some trade-offs that arise from this perspective. We then suggest that public trust is of major importance for population uptake of contact tracing apps. Hasty, ill-prepared or badly communicated implementations of CT apps will likely undermine public trust, and as such, risk impeding general effectiveness.


id: cord-268463-ehp0q0ry
title: Effectiveness of Interventions to Reduce Contact Rates during a Simulated Influenza Pandemic
author: Haber, Michael J.
date: 2007-04-17
txt: ./txt/cord-268463-ehp0q0ry.txt
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extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/17553273/
doi: 10.3201/eid1304.060828
summary:
  We used stochastic simulation models to explore the effects of school closings, voluntary confinements of ill persons and their household contacts, and reductions in contacts among long-term care facility (LTCF) residents on pandemic-related illness and deaths. We used stochastic simulation models to explore the effects of school closings, voluntary confinements of ill persons and their household contacts, and reductions in contacts among long-term care facility (LTCF) residents on pandemic-related illness and deaths. By using these models to simulate an influenza pandemic, we estimated the effects of school closings, home confinement of ill persons (i.e., isolation) or their household contacts (i.e., quarantine), and reduction of contacts among residents of LTCFs on overall illness attack rates, hospitalization rates, and mortality rates. The interventions we examined in this simulation study were school closings, confinement of ill persons and their household contacts to their homes, and reduction in contact rates among residents of LTCFs. Interventions were implemented at the start of the outbreak.

abstract:
  Measures to decrease contact between persons during an influenza pandemic have been included in pandemic response plans. We used stochastic simulation models to explore the effects of school closings, voluntary confinements of ill persons and their household contacts, and reductions in contacts among long-term care facility (LTCF) residents on pandemic-related illness and deaths. Our findings suggest that school closings would not have a substantial effect on pandemic-related outcomes in the absence of measures to reduce out-of-school contacts. However, if persons with influenzalike symptoms and their household contacts were encouraged to stay home, then rates of illness and death might be reduced by ≈50%. By preventing ill LTCF residents from making contact with other residents, illness and deaths in this vulnerable population might be reduced by ≈60%. Restricting the activities of infected persons early in a pandemic could decrease negative health impact.


id: cord-269850-5pidolqb
title: A Smartphone Enabled Approach to Manage COVID-19 Lockdown and Economic Crisis
author: Maghdid, Halgurd S.
date: 2020-08-14
txt: ./txt/cord-269850-5pidolqb.txt
cache: ./cache/cord-269850-5pidolqb.txt
extension: .txt
mime: text/plain
url: https://doi.org/10.1007/s42979-020-00290-0
doi: 10.1007/s42979-020-00290-0
summary:
  1. We build a tracking model based on positional information of registered users to conduct contact-tracing of confirmed COVID-19 cases. The best thing to do seems to be let people go out for their business, but any body tests positive of COVID-19, we would be able, through proposed framework, to trace Fig. 3 A framework of contact-tracing using smartphone-based approach everybody in contact with the confirmed case and managing the lockdown and mass quarantine. In this study, k-means as an unsupervised machine learning algorithm is used to cluster the users'' positions information and predict that the area should be locked down or not based on the same empirical thresholds. This Fig. 6 The results of the prediction model for both scenarios is followed by send back notifications from the server to the users to notify them for the crowded area and controlling the spreading the coronavirus COVID-19.

abstract:
  The emergence of novel COVID-19 causes an over-load in health system and high mortality rate. The key priority is to contain the epidemic and prevent the infection rate. In this context, many countries are now in some degree of lockdown to ensure extreme social distancing of entire population and hence slowing down the epidemic spread. Furthermore, authorities use case quarantine strategy and manual second/third contact-tracing to contain the COVID-19 disease. However, manual contact-tracing is time-consuming and labor-intensive task which tremendously over-load public health systems. In this paper, we developed a smartphone-based approach to automatically and widely trace the contacts for confirmed COVID-19 cases. Particularly, contact-tracing approach creates a list of individuals in the vicinity and notifying contacts or officials of confirmed COVID-19 cases. This approach is not only providing awareness to individuals they are in the proximity to the infected area, but also tracks the incidental contacts that the COVID-19 carrier might not recall. Thereafter, we developed a dashboard to provide a plan for policymakers on how lockdown/mass quarantine can be safely lifted, and hence tackling the economic crisis. The dashboard used to predict the level of lockdown area based on collected positions and distance measurements of the registered users in the vicinity. The prediction model uses k-means algorithm as an unsupervised machine learning technique for lockdown management.


id: cord-275253-6pwqa8zk
title: 10 “C” in COVID19
author: Shetty, Sameep S
date: 2020-05-29
txt: ./txt/cord-275253-6pwqa8zk.txt
cache: ./cache/cord-275253-6pwqa8zk.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/32837534/
doi: 10.1111/ors.12527
summary:
  The contrast in the degree of hypoxia ("silent hypoxia") and the pattern of infections in high-risk individuals who are unable to mount a stable immune response with modest symptoms explains the lethal spectrum of the novel coronavirus. In contrast, initial data on the role of ACE inhibitors augmenting the onset of severe forms of SARS-CoV-2 infection has discouraged their use and triggered the onset of severe cardiovascular events 7,8 . Covid19 in high risk individuals display severe respiratory symptoms, multi organ involvement and may require a long term rehabilitation as in a chronic disease. SARS-CoV-2 Isolation From Ocular Secretions of a Patient With COVID-19 in Italy With Prolonged Viral RNA Detection Cancer patients in SARS-CoV-2 infection: a nationwide analysis in China. The novel coronavirus disease (COVID-19) threat for patients with cardiovascular disease and cancer The oral surgery response to coronavirus disease (COVID-19)

abstract:
  World war “C”(1) has set in against an invisible virus. The routes of transmission include *Contact of contaminated objects,*Circulating droplets in the air called aerosols disseminated through *Cough, sneeze, ocular secretions(2) from an infected individual.


id: cord-276763-x3dqi0ym
title: Measuring Social Contacts in the Emergency Department
author: Lowery-North, Douglas W.
date: 2013-08-21
txt: ./txt/cord-276763-x3dqi0ym.txt
cache: ./cache/cord-276763-x3dqi0ym.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/23990915/
doi: 10.1371/journal.pone.0070854
summary:
  During study observation periods, patients and staff were given RFID tags to wear. We report here the results of a year-long deployment of a RFID system covering all areas of an adult ED, describing the contacts between and among patients and staff. Furthermore, during the twelve-hour study periods, research assistants interacted with the system in real time to locate patients, staff, and equipment. Demographic and clinical characteristics of the patient admission data are shown in Table 1 , summarized for the population over the year, all patients in our 81 sampled shifts, and patient study participants only. Informal observations of interpersonal behavior made by research study staff suggest no change in number or duration of interpersonal contacts. In the study with the most comparable setting and methods, Gundlapalli and colleagues report data on contacts between 1261 patients and 87 staff in a pediatric hospital ED collected over the course of a randomly chosen month [20] .

abstract:
  BACKGROUND: Infectious individuals in an emergency department (ED) bring substantial risks of cross infection. Data about the complex social and spatial structure of interpersonal contacts in the ED will aid construction of biologically plausible transmission risk models that can guide cross infection control. METHODS AND FINDINGS: We sought to determine the number and duration of contacts among patients and staff in a large, busy ED. This prospective study was conducted between 1 July 2009 and 30 June 2010. Two 12-hour shifts per week were randomly selected for study. The study was conducted in the ED of an urban hospital. There were 81 shifts in the planned random sample of 104 (78%) with usable contact data, during which there were 9183 patient encounters. Of these, 6062 (66%) were approached to participate, of which 4732 (78%) agreed. Over the course of the year, 88 staff members participated (84%). A radiofrequency identification (RFID) system was installed and the ED divided into 89 distinct zones structured so copresence of two individuals in any zone implied a very high probability of contact <1 meter apart in space. During study observation periods, patients and staff were given RFID tags to wear. Contact events were recorded. These were further broken down with respect to the nature of the contacts, i.e., patient with patient, patient with staff, and staff with staff. 293,171 contact events were recorded, with a median of 22 contact events and 9 contacts with distinct individuals per participant per shift. Staff-staff interactions were more numerous and longer than patient-patient or patient-staff interactions. CONCLUSIONS: We used RFID to quantify contacts between patients and staff in a busy ED. These results are useful for studies of the spread of infections. By understanding contact patterns most important in potential transmission, more effective prevention strategies may be implemented.


id: cord-283093-9kz7387z
author: Quaife, Matthew
date: 2020-10-05
txt: ./txt/cord-283093-9kz7387z.txt
cache: ./cache/cord-283093-9kz7387z.txt
extension: .txt
mime: text/plain
url: https://doi.org/10.1186/s12916-020-01779-4
doi: 10.1186/s12916-020-01779-4
summary:
  In this study, we collect contact data from residents of informal settlements around Nairobi, Kenya, to assess if control measures have changed contact patterns, and estimate the impact of changes on the basic reproduction number (R(0)). Respondents were asked to report all direct physical and non-physical contacts made the previous day, alongside a questionnaire asking about the social and economic impact of COVID-19 and control measures. Although one social mixing study was conducted in Kilifi, a coastal area of Kenya [21] , outside of one study which collected data from a South African township [16] , no published contact data exist from informal settlements, which may be particularly vulnerable to COVID-19 due to high levels of population density, indoor crowding, and household sizes, alongside intergenerational mixing within the household.

title:
  The impact of COVID-19 control measures on social contacts and transmission in Kenyan informal settlements

abstract:
  BACKGROUND: Many low- and middle-income countries have implemented control measures against coronavirus disease 2019 (COVID-19). However, it is not clear to what extent these measures explain the low numbers of recorded COVID-19 cases and deaths in Africa. One of the main aims of control measures is to reduce respiratory pathogen transmission through direct contact with others. In this study, we collect contact data from residents of informal settlements around Nairobi, Kenya, to assess if control measures have changed contact patterns, and estimate the impact of changes on the basic reproduction number (R(0)). METHODS: We conducted a social contact survey with 213 residents of five informal settlements around Nairobi in early May 2020, 4 weeks after the Kenyan government introduced enhanced physical distancing measures and a curfew between 7 pm and 5 am. Respondents were asked to report all direct physical and non-physical contacts made the previous day, alongside a questionnaire asking about the social and economic impact of COVID-19 and control measures. We examined contact patterns by demographic factors, including socioeconomic status. We described the impact of COVID-19 and control measures on income and food security. We compared contact patterns during control measures to patterns from non-pandemic periods to estimate the change in R(0). RESULTS: We estimate that control measures reduced physical contacts by 62% and non-physical contacts by either 63% or 67%, depending on the pre-COVID-19 comparison matrix used. Masks were worn by at least one person in 92% of contacts. Respondents in the poorest socioeconomic quintile reported 1.5 times more contacts than those in the richest. Eighty-six percent of respondents reported a total or partial loss of income due to COVID-19, and 74% reported eating less or skipping meals due to having too little money for food. CONCLUSION: COVID-19 control measures have had a large impact on direct contacts and therefore transmission, but have also caused considerable economic and food insecurity. Reductions in R(0) are consistent with the comparatively low epidemic growth in Kenya and other sub-Saharan African countries that implemented similar, early control measures. However, negative and inequitable impacts on economic and food security may mean control measures are not sustainable in the longer term.


id: cord-283467-bgxc3ti8
title: Risk of SARS-CoV-2 infection among contacts of individuals with COVID-19 in Hangzhou, China
author: Wu, Yan
date: 2020-06-12
txt: ./txt/cord-283467-bgxc3ti8.txt
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extension: .txt
mime: text/plain
url: https://www.sciencedirect.com/science/article/pii/S0033350620301785?v=s5
doi: 10.1016/j.puhe.2020.05.016
summary:
  title: Risk of SARS-CoV-2 infection among contacts of individuals with COVID-19 in Hangzhou, China Abstract Objectives This study determined the rate of secondary infection among contacts of individuals with confirmed COVID-19 in Hangzhou according to the type of contact, the intensity of the contact, and their relationship with the index patient. Methods The analysis used the data of 2,994 contacts of 144 individuals with confirmed SARS-CoV-2 infection. Centralized isolation and observation of close contacts of individuals with confirmed SARS-CoV-2 infection, in addition to population-based control measures, can reduce the risk of secondary infections and curb the spread of the infection. January 23, 2020, Zhejiang Province was among the first provinces to declare a major public health emergency and introduced ten policies including vigorously promoting public 2 awareness on epidemic prevention, restricting public gatherings, and taking measures to prevent hospital-acquired infections to prevent the transmission of SARS-CoV-2 infection.

abstract:
  Abstract Objectives This study determined the rate of secondary infection among contacts of individuals with confirmed COVID-19 in Hangzhou according to the type of contact, the intensity of the contact, and their relationship with the index patient. Study design Retrospective cohort study. Methods The analysis used the data of 2,994 contacts of 144 individuals with confirmed SARS-CoV-2 infection. The contacts were categorized according to the information source, type of contact, location, intensity of contact, and relationship with the index patient. Results The incidence of infection differed significantly according to contact type. Of the contacts, 186 (6.2%) developed symptoms and 71 (2.4%) had confirmed infection with SARS-CoV-2. The main symptoms were cough and fever. Compared to those who had brief contact with the index case, those who had dined with the index case had a 2.6 times greater risk of infection; those who had shared transport, visited, or had contact with the index case in a medical institution had a 3.6 times greater risk of infection; and household contacts had 41.7 times greater risk of infection. Family members had a 31.6 times greater risk of infection than healthcare providers or other patients exposed to an index case. Conclusions The form and frequency of contact are the main factors affecting the risk of infection among contacts of individuals with COVID-19. Centralized isolation and observation of close contacts of individuals with confirmed SARS-CoV-2 infection, in addition to population-based control measures, can reduce the risk of secondary infections and curb the spread of the infection.


id: cord-285105-72v6qufw
title: The Easter and Passover Blip in New York City
author: Vierlboeck, Maximilian
date: 2020-04-17
txt: ./txt/cord-285105-72v6qufw.txt
cache: ./cache/cord-285105-72v6qufw.txt
extension: .txt
mime: text/plain
url: https://doi.org/10.1101/2020.04.14.20065300
doi: 10.1101/2020.04.14.20065300
summary:
  In numbers, given that increases of 25% and 50% seem to be most likely given the data seen in Germany for the Easter weekend for example [2, 3] , our simulations show the following increases (compared to realistic reference run) for a temporary 25% surge in contact rate: the total cases grew by 215,880, the maximum of required hospitalizations over time increased to 63,063, and the total climb in fatalities was 8,844 accumulated over 90 days. In numbers, given that increases of 25% and 50% seem to be most likely given the data seen in Germany for the Easter weekend for example [2, 3] , our simulations show the following increases (compared to realistic reference run) for a temporary 25% surge in contact rate: the total cases grew by 215,880, the maximum of required hospitalizations over time increased to 63,063, and the total climb in fatalities was 8,844 accumulated over 90 days.

abstract:
  Abstract and Executive Summary - When it comes to pandemics such as the currently present COVID-19 [1], various issues and problems arise for infrastructures and institutions. Due to possible extreme effects, such as hospitals potentially running out of beds or medical equipment, it is essential to lower the infection rate to create enough space to attend to the affected people and allow enough time for a vaccine to be developed. Unfortunately, this requires that measures put into place are upheld long enough to reduce the infection rate sufficiently. In this paper, we describe research simulating the influences of the contact rate on the spread of the pandemic using New York City as an example (Section IV) and especially already observed effects of contact rate increases during holidays [2-4] (Section V). In multiple simulations scenarios for Passover and Easter holidays, we evaluated 25%, 50%, 75%, and 100% temporary increases in contact rates using a scenario close to the currently reported numbers as reference and contact rates based on bioterrorism research as a 'normal' baseline for NYC. The first general finding from the simulations is that singular events of increased visits/contacts amplify each other disproportionately if they are happening in close proximity (time intervals) together. The second general observation was that contact rate spikes leave a permanently increased and devastating infection rate behind, even after the contact rate returns to the reduced one. In case of a temporary sustained increase of contact rate for just three days in a row, the aftermath results in an increase of infection rate up to 40%, which causes double the fatalities in the long run. In numbers, given that increases of 25% and 50% seem to be most likely given the data seen in Germany for the Easter weekend for example [2, 3], our simulations show the following increases (compared to the realistic reference run): for a temporary 25% surge in contact rate, the total cases grew by 215,880, the maximum of required hospitalizations over time increased to 63,063, and the total fatalities climbed by 8,844 accumulated over 90 days. As for the 50% surge, we saw the total number of cases rise by 461,090, the maximum number of required hospitalizations increase to 79,733, and the total number of fatalities climb by 19,125 over 90 days in NYC. All in all, we conclude that even very short, temporary increases in contact rates can have disproportionate effects and result in unrecoverable phenomena that can hardly be reversed or managed later. The numbers show possible phenomena before they might develop effects in reality. This is important because phenomena such as the described blip can impact the hospitals in reality. Therefore, we warn that a wave of infections due to increased contact rates during Passover/Easter might come as a result!


id: cord-286070-qwq46b8a
title: Ring Vaccination and Smallpox Control
author: Kretzschmar, Mirjam
date: 2004-05-17
txt: ./txt/cord-286070-qwq46b8a.txt
cache: ./cache/cord-286070-qwq46b8a.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/15200816/
doi: 10.3201/eid1005.030419
summary:
  The basic reproduction number R 0 describes the average number of secondary cases produced from contact with an infected person during the infectious period and without intervention. The effectiveness of the intervention therefore is determined by the probability of diagnosis per day of the infectious period, the time needed to identify contacts of the close contact and casual contact ring, the vaccination coverage in the close contact and the casual contact ring, and whether contacts are monitored. Our simulation results show that a smallpox epidemic starting from a small number of index cases can be contained by ring vaccination provided the intervention measures are very effective. Here the critical vaccination coverage in the casual contact ring is shown as a function of the basic reproduction number R 0 for different assumptions about the time it takes to diagnose infectious persons.

abstract:
  We present a stochastic model for the spread of smallpox after a small number of index cases are introduced into a susceptible population. The model describes a branching process for the spread of the infection and the effects of intervention measures. We discuss scenarios in which ring vaccination of direct contacts of infected persons is sufficient to contain an epidemic. Ring vaccination can be successful if infectious cases are rapidly diagnosed. However, because of the inherent stochastic nature of epidemic outbreaks, both the size and duration of contained outbreaks are highly variable. Intervention requirements depend on the basic reproduction number R(0), for which different estimates exist. When faced with the decision of whether to rely on ring vaccination, the public health community should be aware that an epidemic might take time to subside even for an eventually successful intervention strategy.


id: cord-295293-ickp2n47
title: Evolving social contact patterns during the COVID-19 crisis in Luxembourg
author: Latsuzbaia, Ardashel
date: 2020-08-06
txt: ./txt/cord-295293-ickp2n47.txt
cache: ./cache/cord-295293-ickp2n47.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/32760114/
doi: 10.1371/journal.pone.0237128
summary:
  While the number of social contacts was substantially lower during the lockdown by more than 80% compared to the pre-pandemic period, we observed a more recent 121% increase during the post lockdown period showing an increased potential for COVID-19 spread. We repeatedly conducted an internet survey to follow up the impact of the local government interventions on social contact patterns in Luxembourg shortly after the lockdown was implemented due to the rapid local spread of the COVID-19. The average number of contacts reported by Luxembourg residents in a study before the pandemic was 17.5 [4] , suggesting that contacts during lockdown had decreased by 81.7%. Our study suggests that the strict physical distancing measures implemented in Luxembourg had a substantial and immediate impact on social mixing patterns resulting in a large reduction of the average number of contacts per day. In conclusion, our stud shows that physical distance measures resulted in significant reduction in social contacts and therefore decreased the spread of COVID-19 in Luxembourg.

abstract:
  We conducted an internet survey using Survey Monkey over six weeks to evaluate the impact of the government interventions on social contact patterns in Luxembourg. Participants were recruited via the science.lu website on March 25, April 2, April 16, May 1 during lockdown, and June 12 and June 25 after the lockdown to provide an estimate of their number of contacts within the previous 24 hours. During the lockdown, a total of 5,644 survey participants with a mean age of 44.2 years reported 18,118 contacts (mean = 3.2, IQR 1–4). The average number of contacts per day increased by 24% from 2.9 to 3.6 over the lockdown period. The average number of contacts decreased with age: 4.2 (IQR 2–5) for participants below 25 years and 1.7 (IQR 1–2) for participants above 64 years. Residents of Portuguese nationality reported a higher number of contacts (mean = 4.3, IQR 2–5) than Luxembourgish (mean = 3.5, IQR 2–4) or other foreign residents, respectively. After lockdown, 1,119 participants reported 7,974 contacts with 7.1 (IQR 3–9) contacts per day on average, of which 61.7% (4,917/7,974) occurred without a facemask (mean = 4.9, IQR 2–6). While the number of social contacts was substantially lower during the lockdown by more than 80% compared to the pre-pandemic period, we observed a more recent 121% increase during the post lockdown period showing an increased potential for COVID-19 spread. Monitoring social contacts is an important indicator to estimate the possible impact of government interventions on social contacts and the COVID-19 spread in the coming months.


id: cord-296487-m4xba78g
title: Health system capacity in Sydney, Australia in the event of a biological attack with smallpox
author: MacIntyre, Chandini Raina
date: 2019-06-14
txt: ./txt/cord-296487-m4xba78g.txt
cache: ./cache/cord-296487-m4xba78g.txt
extension: .txt
mime: text/plain
url: https://doi.org/10.1371/journal.pone.0217704
doi: 10.1371/journal.pone.0217704
summary:
  If the response is delayed, or if the attack infects 10000 people, all available beds will be exceeded within 40 days, with corresponding surge requirements for clinical health care workers (HCWs). Specifically, we aimed to determine hospital bedcapacity for isolation, public health workforce capacity for contact tracing and health care worker (HCW) personal protective equipment (PPE) requirements under different attack scenarios. We estimated number of hospital beds needed to control the epidemic, PPE requirements for clinical HCWs and public health workers required for contact tracing, under different scenarios. The number of hospital beds needed for case isolation was then modelled under different scenarios based on variation of response time (T), the percentage of infected cases isolated each day and how many contacts were traced. The number of contacts needed to be traced and managed was estimated based on attack size, time to response (T) and the percentage of infected cases isolated each day.

abstract:
  Planning for a re-emergent epidemic of smallpox requires surge capacity of space, resources and personnel within health systems. There are many uncertainties in such a scenario, including likelihood and size of an attack, speed of response and health system capacity. We used a model for smallpox transmission to determine requirements for hospital beds, contact tracing and health workers (HCWs) in Sydney, Australia, during a modelled epidemic of smallpox. Sensitivity analysis was done on attack size, speed of response and proportion of case isolation and contact tracing. We estimated 100638 clinical HCWs and 14595 public hospital beds in Sydney. Rapid response, case isolation and contact tracing are influential on epidemic size, with case isolation more influential than contact tracing. With 95% of cases isolated, outbreak control can be achieved within 100 days even with only 50% of contacts traced. However, if case isolation and contact tracing both fall to 50%, epidemic control is lost. With a smaller initial attack and a response commencing 20 days after the attack, health system impacts are modest. The requirement for hospital beds will vary from up to 4% to 100% of all available beds in best and worst case scenarios. If the response is delayed, or if the attack infects 10000 people, all available beds will be exceeded within 40 days, with corresponding surge requirements for clinical health care workers (HCWs). We estimated there are 330 public health workers in Sydney with up to 940,350 contacts to be traced. At least 3 million respirators will be needed for the first 100 days. To ensure adequate health system capacity, rapid response, high rates of case isolation, excellent contact tracing and vaccination, and protection of HCWs should be a priority. Surge capacity must be planned. Failures in any of these could cause health system failure, with inadequate beds, quarantine spaces, personnel, PPE and inability to manage other acute health conditions.


id: cord-297612-swc2pitd
author: Nosyk, Bohdan
date: 2020-04-27
txt: ./txt/cord-297612-swc2pitd.txt
cache: ./cache/cord-297612-swc2pitd.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/32339245/
doi: 10.1093/cid/ciaa501
summary:
  title: Contact tracing for COVID-19: An opportunity to reduce health disparities and End the HIV/AIDS Epidemic in the US We argue that COVID-19 contact tracing may provide a unique opportunity to also conduct widespread HIV testing, among other health promotion activities. M a n u s c r i p t Massive SARS-CoV2 testing and contact tracing at a scale and speed never before seen have been proposed as critical components of a COVID-19 public health strategy that could, in theory, safely allow us to relax social distancing measures and begin to bring back the world we left behind before a cure or effective vaccine is delivered. Aside from the potentially profound health benefits of a combination implementation approach, pairing COVID-19 contact tracing with testing for HIV may serve to offset the immense costs of such an approach.

title:
  Contact tracing for COVID-19: An opportunity to reduce health disparities and End the HIV/AIDS Epidemic in the US

abstract:
  SARS-CoV2 testing and contact tracing have been proposed as critical components of a safe and effective COVID-19 public health strategy. We argue that COVID-19 contact tracing may provide a unique opportunity to also conduct widespread HIV testing, among other health promotion activities.


id: cord-306284-bj8u0dtk
author: Kimathi, Mark
date: 2020-11-10
txt: ./txt/cord-306284-bj8u0dtk.txt
cache: ./cache/cord-306284-bj8u0dtk.txt
extension: .txt
mime: text/plain
url: https://api.elsevier.com/content/article/pii/S246804272030066X
doi: 10.1016/j.idm.2020.10.012
summary:
  Similar to other countries in sub-Saharan Africa, the Kenyan government has imposed travel restrictions across counties, dusk-to-dawn curfew and school closure to ensure social distancing in the population and consequently slowed transmission of COVID-19. In this study, an age-structured SEIR mathematical model that examines the impact of NPIs in curbing COVID-19 severity and deaths in Kenya is developed, with the aim of achieving the following; (i) assessing the impact of reducing social contacts in different age-groups, (ii) examining the trend in infections during and after the NPIs, (iii) providing plausible period for lifting the NPIs. We postulate that this study can form a basis for policy formulation to enable Kenya delay the disease transmission and eventually flatten the epidemic curve. To show the impact of the highlighted measures in Kenya, we present results for daily and cumulative infections, severe and critical cases, deaths, as well as peak demand for hospital and ICU beds.

title:
  Age-structured model for COVID-19: Effectiveness of social distancing and contact reduction in Kenya

abstract:
  Coronavirus disease 2019 is caused by severe acute respiratory syndrome coronavirus 2. Kenya reported its first case on March 13, 2020 and by March 16, 2020 she instituted physical distancing strategies to reduce transmission and flatten the epidemic curve. An age-structured compartmental model was developed to assess the impact of the strategies on COVID-19 severity and burden. Contacts between different ages are incorporated via contact matrices. Simulation results show that 45% reduction in contacts for 60-days period resulted to 11.5–13% reduction of infections severity and deaths, while for the 190-days period yielded 18.8–22.7% reduction. The peak of infections in the 60-days mitigation was higher and happened about 2 months after the relaxation of mitigation as compared to that of the 190-days mitigation, which happened a month after mitigations were relaxed. Low numbers of cases in children under 15 years was attributed to high number of asymptomatic cases. High numbers of cases are reported in the 15–29 years and 30–59 years age bands. Two mitigation periods, considered in the study, resulted to reductions in severe and critical cases, attack rates, hospital and ICU bed demands, as well as deaths, with the 190-days period giving higher reductions.


id: cord-306784-0cmekxs0
author: Malmberg, Hannes
date: 2020-09-09
txt: ./txt/cord-306784-0cmekxs0.txt
cache: ./cache/cord-306784-0cmekxs0.txt
extension: .txt
mime: text/plain
url: https://doi.org/10.1098/rsif.2020.0351
doi: 10.1098/rsif.2020.0351
summary:
  title: Inflow restrictions can prevent epidemics when contact tracing efforts are effective but have limited capacity When a region tries to prevent an outbreak of an epidemic, two broad strategies are available: limiting the inflow of infected cases by using travel restrictions and quarantines or limiting the risk of local transmission from imported cases by using contact tracing and other community interventions. Regulating λ is particularly important when the contact tracing system is close to being overwhelmed by new cases arriving from elsewhere, in which case even moderate reductions in λ can strongly reduce the probability of an epidemic outbreak. By contrast, if contact tracing is effective but has limited capacity, there can still be an epidemic because of an overload of the system, and travel restrictions will affect the probability that such an overload happens.

title:
  Inflow restrictions can prevent epidemics when contact tracing efforts are effective but have limited capacity

abstract:
  When a region tries to prevent an outbreak of an epidemic, two broad strategies are available: limiting the inflow of infected cases by using travel restrictions and quarantines or limiting the risk of local transmission from imported cases by using contact tracing and other community interventions. A number of papers have used epidemiological models to argue that inflow restrictions are unlikely to be effective. We simulate a simple epidemiological model to show that this conclusion changes if containment efforts such as contact tracing have limited capacity. In particular, our results show that moderate travel restrictions can lead to large reductions in the probability of an epidemic when contact tracing is effective but the contact tracing system is close to being overwhelmed.


id: cord-307342-3gkiukh4
title: Why contact tracing efforts have failed to curb COVID-19 transmission in much of the U.S
author: Clark, Eva
date: 2020-08-06
txt: ./txt/cord-307342-3gkiukh4.txt
cache: ./cache/cord-307342-3gkiukh4.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/32761123/
doi: 10.1093/cid/ciaa1155
summary:
  By late April 2020, public discourse in the U.S. had shifted toward the idea of using more targeted case-based mitigation tactics (e.g., contact tracing) to combat COVID-19 transmission while allowing for the safe "re-opening" of society, in an effort to reduce the social, economic, and political ramifications associated with stricter approaches. This viewpoint offers a discussion of why testing-tracing efforts failed to sufficiently mitigate COVID-19 across much of the nation, with the hope that such deliberation will help the U.S. public health community better plan for the future. Partly for this reason, our nation rushed to espouse the idea of targeted, case-based COVID-19 management [3] [4] [5] [6] , focusing on expanded testing and contact tracing, while disregarding several major obstacles that set us apart from countries that succeeded in mounting a timely, targeted response.

abstract:
  By late April 2020, public discourse in the U.S. had shifted toward the idea of using more targeted case-based mitigation tactics (e.g., contact tracing) to combat COVID-19 transmission while allowing for the safe “re-opening” of society, in an effort to reduce the social, economic, and political ramifications associated with stricter approaches. Expanded tracing-testing efforts were touted as a key solution that would allow for a precision approach, thus preventing economies from having to shut down again. However, it is now clear that many regions of the U.S. were unable to mount robust enough testing-tracing programs to prevent major resurgences of disease. This viewpoint offers a discussion of why testing-tracing efforts failed to sufficiently mitigate COVID-19 across much of the nation, with the hope that such deliberation will help the U.S. public health community better plan for the future.


id: cord-314746-1o0rf0ii
title: Interdiction of Protein Folding for Therapeutic Drug Development in SARS CoV-2
author: Bergasa-Caceres, Fernando
date: 2020-08-10
txt: ./txt/cord-314746-1o0rf0ii.txt
cache: ./cache/cord-314746-1o0rf0ii.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/32790379/
doi: 10.1021/acs.jpcb.0c03716
summary:
  [Image: see text] In this article, we predict the folding initiation events of the ribose phosphatase domain of protein Nsp3 and the receptor binding domain of the spike protein from the severe acute respiratory syndrome (SARS) coronavirus-2. The identification of the primary contacts along the folding pathway of viral proteins constitutes an important result for at least two reasons: (a) the sequences of the specific segments involved in the primary contacts provide a template to specify candidate peptide drugs of inhibitory effect with the maximum possible contact affinity to compete with the natural folding mechanism; and (b) it provides insight for further investigation into the subsequent folding steps leading to a fully functional viral protein, potentially providing for additional FITRs. The fact that the primary contact is defined by the interaction between two well defined amino acid sequences suggests that a strategy to develop FITR-based therapeutic drugs could be one utilizing trial peptide drugs as suggested above.

abstract:
  [Image: see text] In this article, we predict the folding initiation events of the ribose phosphatase domain of protein Nsp3 and the receptor binding domain of the spike protein from the severe acute respiratory syndrome (SARS) coronavirus-2. The calculations employ the sequential collapse model and the crystal structures to identify the segments involved in the initial contact formation events of both viral proteins. The initial contact locations may provide good targets for therapeutic drug development. The proposed strategy is based on a drug binding to the contact location, thereby aiming to prevent protein folding. Peptides are suggested as a natural choice for such protein folding interdiction drugs.


id: cord-315466-74m7cur3
title: Potential reduction in transmission of COVID-19 by digital contact tracing systems
author: Plank, M. J.
date: 2020-09-01
txt: ./txt/cord-315466-74m7cur3.txt
cache: ./cache/cord-315466-74m7cur3.txt
extension: .txt
mime: text/plain
url: https://doi.org/10.1101/2020.08.27.20068346
doi: 10.1101/2020.08.27.20068346
summary:
  We use an age-structured branching process model of the transmission of COVID-19 in different settings to estimate the potential of manual contact tracing and digital tracing systems to help control the epidemic. We investigate the effect of the uptake rate and proportion of contacts recorded by the digital system on key model outputs: the effective reproduction number, the mean outbreak size after 30 days, and the probability of elimination. While contact tracing alone is unlikely to contain the spread of COVID-19 Kucharski et al., 2020) , in countries like New Zealand where cases have been reduced to very low numbers (Cousins, 2020; Binny et al., 2020) , it may allow population-wide social distancing measures to be relaxed. Manual-only contact tracing (which corresponds to a digital uptake rate of = 0 in Fig. 3 ) with moderately (50%) effective quarantine of pre-symptomatic or subclinical individuals reduced to 1.55, the mean outbreak size to approximately 34 and increased the probability of extinction to 67%.

abstract:
  Digital tools are being developed to support contact tracing as part of the global effort to control the spread of COVID-19. These include smartphone apps, Bluetooth-based proximity detection, location tracking, and automatic exposure notification features. Evidence on the effectiveness of alternative approaches to digital contact tracing is so far limited. We use an age-structured branching process model of the transmission of COVID-19 in different settings to estimate the potential of manual contact tracing and digital tracing systems to help control the epidemic. We investigate the effect of the uptake rate and proportion of contacts recorded by the digital system on key model outputs: the effective reproduction number, the mean outbreak size after 30 days, and the probability of elimination. We show that effective manual contact tracing can reduce the effective reproduction number from 2.4 to around 1.5. The addition of a digital tracing system with a high uptake rate over 75% could further reduce the effective reproduction number to around 1.1. Fully automated digital tracing without manual contact tracing is predicted to be much less effective. We conclude that, for digital tracing systems to make a significant contribution to the control of COVID-19, they need be designed in close conjunction with public health agencies to support and complement manual contact tracing by trained professionals.


id: cord-319023-ucm8frol
author: Nuzzo, Andrea
date: 2020-06-22
txt: ./txt/cord-319023-ucm8frol.txt
cache: ./cache/cord-319023-ucm8frol.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/32861334/
doi: 10.1016/j.mayocp.2020.06.027
summary:
  Model parameters included percentage population ordered to shelter-in-place, adoption rate of AACT, and percentage individuals who appropriately follow recommendations. Conclusion Wide adoption of digital contact tracing can mitigate infection spread similar to universal shelter-in-place, but with considerably fewer individuals isolated. Such Advanced Automated Contact Tracing (AACT) systems -which could infer exposure risk and propagate warnings to people at risk -may help curb disease spread by facilitating targeted self-isolation rather than universal mandates such as shelter-inplace. In AACT, an additional compartment Sq (Traced contacts that are exposed and under selfisolation) was used while for shelter-in-place, the compartment Q (Individuals isolated through universal enforcement measures) was used. The basic difference between the models is that isolation/quarantine is based solely on exposure history in AACT, while isolation orders apply to the entire population in universal shelter-in-place. Contact tracing can mitigate disease spread through a curated approach of identifying and isolating exposed individuals, as opposed to shelter-in-place orders.

title:
  Universal Shelter-in-Place vs. Advanced Automated Contact Tracing and Targeted Isolation: A Case for 21st-Century Technologies for SARS-CoV-2 and Future Pandemics

abstract:
  Abstract Objective To model and compare effect of digital contact tracing versus shelter-in-place on SARS-CoV-2 spread. Methods Using a classical epidemiologic framework, and parameters estimated from literature published between February 1, 2020 and May 25, 2020, we modeled two non-pharmacologic interventions- shelter-in-place and digital contact tracing- to curb spread of SARS-CoV-2. For contact tracing, we assumed an advanced, automated contact tracing (AACT) application that sends alerts to individuals advising self-isolation based on individual exposure profile. Model parameters included percentage population ordered to shelter-in-place, adoption rate of AACT, and percentage individuals who appropriately follow recommendations. Under influence of these variables, number of individuals infected, exposed, and isolated were estimated. Results Without any intervention, a high rate of infection (>10 million) with early peak is predicted. Shelter-in-place results in rapid decline in infection rate at the expense of impacting a large population segment. The AACT model achieves reduction in infected and exposed individuals similar to shelter-in-place without impacting a large number of individuals. For example, a 50% AACT adoption rate mimics a shelter-in-place order for 40% of the population and results in >90% decrease in peak number of infections. However, as compared to shelter-in-place, with AACT significantly fewer individuals would be isolated. Conclusion Wide adoption of digital contact tracing can mitigate infection spread similar to universal shelter-in-place, but with considerably fewer individuals isolated.


id: cord-322806-g01wmmbx
title: Testing, tracing and isolation in compartmental models
author: Sturniolo, S.
date: 2020-05-19
txt: ./txt/cord-322806-g01wmmbx.txt
cache: ./cache/cord-322806-g01wmmbx.txt
extension: .txt
mime: text/plain
url: https://doi.org/10.1101/2020.05.14.20101808
doi: 10.1101/2020.05.14.20101808
summary:
  This paper presents a new method for accurately including the effects of Testing, contact-Tracing and Isolation (TTI) strategies in standard compartmental models. It provides a logical framework for understanding the propagation of an May 14, 2020 1/23 infectious disease through a population and allows different interventions to be explored, including testing and contact tracing of infected individuals as possible strategies to ease social distancing restrictions. In this paper we develop an extension to the classic Susceptible-Exposed-Infectious-Removed 1 (SEIR) model [16, 52, 53] simulated with ODEs to include testing, contacttracing, and isolation (TTI) strategies. To answer this we adapt the standard Susceptible-Exposed-Infectious-Removed (SEIR) compartmental model [16, 52] to incorporate contact tracing as well as testing and isolation of cohorts of people. Overlapping compartments represent model states that are not mutually exclusive, so that it is possible for an individual to belong in more than one of them e.g. be infected and contact-traced, or exposed and tested.

abstract:
  Existing compartmental mathematical modelling methods for epidemics, such as SEIR models, cannot accurately represent effects of testing, contact tracing and isolation. This makes them inappropriate for evaluating testing and contact tracing strategies to contain an outbreak. An alternative used in practice is the application of agent- or individual-based models (ABM). However ABMs are complex, less well-understood and much more computationally expensive. This paper presents a new method for accurately including the effects of Testing, contact-Tracing and Isolation (TTI) strategies in standard compartmental models. We derive our method using a careful probabilistic argument to show how contact tracing at the individual level is reflected in aggregate on the population level. We show that the resultant SEIR-TTI model accurately approximates the behaviour of a mechanistic agent-based model at far less computational cost. The computationally efficiency is such that it be easily and cheaply used for exploratory modelling to quantify the required levels of testing and tracing, alone and with other interventions, to assist adaptive planning for managing disease outbreaks.


id: cord-323766-oyyj35bl
author: Parker, Michael J
date: 2020-05-04
txt: ./txt/cord-323766-oyyj35bl.txt
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url: https://www.ncbi.nlm.nih.gov/pubmed/32366705/
doi: 10.1136/medethics-2020-106314
summary:
  In this paper, our aim is to set out a number of ethical considerations relevant to the use of mobile phone apps to enable rapid contact tracing. Any consideration of the ethical questions arising in the context of the COVID-19 pandemic has to place great importance on the moral significance of its international spread and the massive scale ii The effectiveness and reach of any implementation of the app in democratic societies will inevitably be affected by varying configurations of state-citizen relationships, as well as by the roles of civil society groups and non-governmental actors. In this paper, we have set out a number of pressing ethical questions raised by the proposed use of a mobile phone app, the collection of proximity data for the control of the COVID-19 pandemic, and the safe emergence of populations from government-imposed lockdowns.

title:
  Ethics of instantaneous contact tracing using mobile phone apps in the control of the COVID-19 pandemic

abstract:
  In this paper we discuss ethical implications of the use of mobile phone apps in the control of the COVID-19 pandemic. Contact tracing is a well-established feature of public health practice during infectious disease outbreaks and epidemics. However, the high proportion of pre-symptomatic transmission in COVID-19 means that standard contact tracing methods are too slow to stop the progression of infection through the population. To address this problem, many countries around the world have deployed or are developing mobile phone apps capable of supporting instantaneous contact tracing. Informed by the on-going mapping of ‘proximity events’ these apps are intended both to inform public health policy and to provide alerts to individuals who have been in contact with a person with the infection. The proposed use of mobile phone data for ‘intelligent physical distancing’ in such contexts raises a number of important ethical questions. In our paper, we outline some ethical considerations that need to be addressed in any deployment of this kind of approach as part of a multidimensional public health response. We also, briefly, explore the implications for its use in future infectious disease outbreaks.


id: cord-326579-vz8n2jsj
title: Efficacy of contact tracing for the containment of the 2019 novel coronavirus (COVID-19)
author: Keeling, Matt J
date: 2020-06-22
txt: ./txt/cord-326579-vz8n2jsj.txt
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url: https://doi.org/10.1136/jech-2020-214051
doi: 10.1136/jech-2020-214051
summary:
  Results Taking recent estimates for COVID-19 transmission we predict that under effective contact tracing less than 1 in 6 cases will generate any subsequent untraced infections, although this comes at a high logistical burden with an average of 36 individuals traced per case. Results Taking recent estimates for COVID-19 transmission we predict that under effective contact tracing less than 1 in 6 cases will generate any subsequent untraced infections, although this comes at a high logistical burden with an average of 36 individuals traced per case. Conclusions The current contact tracing strategy within the UK is likely to identify a sufficient proportion of infected individuals such that subsequent spread could be prevented, although the ultimate success will depend on the rapid detection of cases and isolation of contacts. 7 8 Here we leverage detailed social network data from the UK to model both transmission and the act of tracing, and identify the implications of early contact tracing for containment of a novel pathogen, using parameters for the novel coronavirus (COVID-19).

abstract:
  OBJECTIVE: Contact tracing is a central public health response to infectious disease outbreaks, especially in the early stages of an outbreak when specific treatments are limited. Importation of novel coronavirus (COVID-19) from China and elsewhere into the UK highlights the need to understand the impact of contact tracing as a control measure. DESIGN: Detailed survey information on social encounters from over 5800 respondents is coupled to predictive models of contact tracing and control. This is used to investigate the likely efficacy of contact tracing and the distribution of secondary cases that may go untraced. RESULTS: Taking recent estimates for COVID-19 transmission we predict that under effective contact tracing less than 1 in 6 cases will generate any subsequent untraced infections, although this comes at a high logistical burden with an average of 36 individuals traced per case. Changes to the definition of a close contact can reduce this burden, but with increased risk of untraced cases; we find that tracing using a contact definition requiring more than 4 hours of contact is unlikely to control spread. CONCLUSIONS: The current contact tracing strategy within the UK is likely to identify a sufficient proportion of infected individuals such that subsequent spread could be prevented, although the ultimate success will depend on the rapid detection of cases and isolation of contacts. Given the burden of tracing a large number of contacts to find new cases, there is the potential the system could be overwhelmed if imports of infection occur at a rapid rate.


id: cord-332194-97tkyv3w
author: Barrett, Peter M
date: 2020-06-11
txt: ./txt/cord-332194-97tkyv3w.txt
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url: https://www.ncbi.nlm.nih.gov/pubmed/32553064/
doi: 10.2807/1560-7917.es.2020.25.23.2000972
summary:
  We report the effectiveness of automated text messaging for active surveillance of asymptomatic close contacts of coronavirus disease (COVID-19) cases in the Cork/Kerry region of Ireland. As part of ongoing efforts to control the spread of infection, national and international guidance recommends active surveillance of asymptomatic close contacts of confirmed cases of COVID-19 [3] [4] [5] [6] [7] . However, evidence for the effectiveness of active surveillance systems among community-based close contacts of cases of COVID-19 has been limited to date. This study aimed to measure the effectiveness of an automated text-based active surveillance system which was used in Cork/ Kerry for the first 7 weeks of the COVID-19 response. In the first 7 weeks of the COVID-19 response in Cork/Kerry, 9.0% of close contacts who consented to participate in active surveillance were referred for testing and 2.6% tested positive for COVID-19. Automated active surveillance systems can thus facilitate early identification of symptomatic close contacts and positive cases of COVID-19.

title:
  Measuring the effectiveness of an automated text messaging active surveillance system for COVID-19 in the south of Ireland, March to April 2020

abstract:
  We report the effectiveness of automated text messaging for active surveillance of asymptomatic close contacts of coronavirus disease (COVID-19) cases in the Cork/Kerry region of Ireland. In the first 7 weeks of the COVID-19 outbreak, 1,336 close contacts received 12,421 automated texts. Overall, 120 contacts (9.0%) reported symptoms which required referral for testing and 35 (2.6%) tested positive for COVID-19. Non-response was high (n = 2,121; 17.1%) and this required substantial clinical and administrative resources for follow-up.


id: cord-335518-ti889uye
title: Contact lens wear and care in Spain during the COVID-19 pandemic
author: Vianya-Estopa, Marta
date: 2020-11-11
txt: ./txt/cord-335518-ti889uye.txt
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mime: text/plain
url: https://www.sciencedirect.com/science/article/pii/S1367048420301946?v=s5
doi: 10.1016/j.clae.2020.11.001
summary:
  Modifiable factors that need particular attention in Spain include: handwashing for at least 20 seconds before lens handling, drying hands with single use paper towels, including a rub-and-rinse step for reusable lenses, lens case cleaning and renewal, avoidance of water exposure and when to cease lens wear during the pandemic. The aim of the current study was to evaluate by means of a survey the behaviours associated with contact lens wear (compliance with hand hygiene and adherence to contact lens wear and care recommendations) as well as to elucidate the best ways to support wearers during the COVID-19 pandemic in Spain. The questions related to lens care disinfection and lens case care were only displayed if the participant used reusable CLs. The final section focused on assessing concerns J o u r n a l P r e -p r o o f associated with contact lens wear and ways to best support wearers during the COVID-19

abstract:
  AIM: To establish contact lens wear and care practices during the COVID-19 pandemic in Spain. METHOD: A 58-item anonymous online survey was distributed during the period 30th April to 10(th) May via Qualtrics. The survey explored: a) demographic characteristics (age, sex, general health and where they were living during lockdown), b) changes in their contact lens use during lockdown, c) hygiene and contact lens compliance and d) concerns associated with contact lens wear and ways to support wearers during the pandemic. RESULTS: Two hundred and sixty responses were analysed (38.8 ± 11.4 years old, 75% female). Three-quarters of participants reported that they were self-isolating or rigorously following social distance advice. Sixty-seven percent of participants reported using their contact lenses less during the pandemic. Respondents were found to be compliant with handwashing prior to inserting and removing contact lenses (in both cases 97% doing this ‘most times’ or ‘every time’). However, only 44% complied with the’ 20 second rule’ and 48% used a shared towel to dry their hands. A higher proportion of hydrogen peroxide users replaced the lens case monthly compared to multi-purpose users (64% vs.49%; p < 0.001). Twenty-four percent admitted wearing lenses whilst showering and 16% did not consider ceasing lens wear if feeling unwell with flu/cold symptoms. CONCLUSION: Eye care practitioners should continue to educate contact lens wearers to ensure safe contact lens wear to minimise the chance of developing contact lens related complications during the pandemic. Modifiable factors that need particular attention in Spain include: handwashing for at least 20 seconds before lens handling, drying hands with single use paper towels, including a rub-and-rinse step for reusable lenses, lens case cleaning and renewal, avoidance of water exposure and when to cease lens wear during the pandemic.


id: cord-337100-45qr0sak
author: Ferrari, A.
date: 2020-05-19
txt: ./txt/cord-337100-45qr0sak.txt
cache: ./cache/cord-337100-45qr0sak.txt
extension: .txt
mime: text/plain
url: https://doi.org/10.1101/2020.05.14.20101675
doi: 10.1101/2020.05.14.20101675
summary:
  We built an expanded SIR model of COVID-19 epidemics that accounts for region-specific population densities, and we used it to test the impact of a contact-tracing app in a number of scenarios. Our results show that, in support of efficient isolation of symptomatic cases, app-mediated contact-tracing can improve containment and achieve successful epidemic mitigation even with relatively small fraction of the population using it, and, with increasing penetrance of its adoption, suppression. In this proof-of-concept study we built a comprehensive framework to model the COVID-19 epidemic, taking into account population density, the different contributions of symptomatic, pre-symptomatic and asymptomatic contagions, and we used it to test the efficacy of targeted intervention such as the aforementioned contact tracing app. We built an improved Susceptible-Infectious-Recovered (SIR) model with the aims of a) faithfully reproducing the dynamics of the SARS-CoV-2 epidemics, including the respective roles of asymptomatic infection and population density; b) test the effects of specific interventions, and specifically the use of phone apps for contact tracing.

title:
  Reproducing SARS-CoV-2 epidemics byregion-specific variables and modeling contacttracing App containment

abstract:
  Targeted contact-tracing through mobile phone apps has been proposed as an instrument to help contain the spread of COVID-19 and manage the lifting of nation-wide lockdowns currently in place in USA and Europe. However, there is an ongoing debate on its potential efficacy, especially in the light of region-specific demographics. We built an expanded SIR model of COVID-19 epidemics that accounts for region-specific population densities, and we used it to test the impact of a contact-tracing app in a number of scenarios. Using demographic and mobility data from Italy and Spain, we used the model to simulate scenarios that vary in baseline contact rates, population densities and fraction of app users in the population. Our results show that, in support of efficient isolation of symptomatic cases, app-mediated contact-tracing can improve containment and achieve successful epidemic mitigation even with relatively small fraction of the population using it, and, with increasing penetrance of its adoption, suppression. However, when regional differences in population density are taken into consideration, the epidemic can be significantly harder to contain in higher density areas, highlighting potential limitations of this intervention in specific contexts. This work corroborates previous results in favor of app-mediated contact-tracing as mitigation measure for COVID-19, and draw attention on the importance of region-specific demographic and mobility factors to achieve maximum efficacy in containment policies.


id: cord-339405-sj7dd6jr
author: Grantz, K. H.
date: 2020-07-14
txt: ./txt/cord-339405-sj7dd6jr.txt
cache: ./cache/cord-339405-sj7dd6jr.txt
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mime: text/plain
url: https://doi.org/10.1101/2020.07.12.20151696
doi: 10.1101/2020.07.12.20151696
summary:
  To increase the evidence base supporting specific methods to measure social interaction, we compared data from self-reported contact surveys and wearable proximity sensors from a cohort of schoolchildren in the Pittsburgh metropolitan area. While proximity sensors and survey methods may not be interchangeable for capturing individual contacts, they can generate highly correlated data on age-specific mixing patterns relevant to the dynamics of respiratory virus transmission. Transmission models 187 When used in age-specific simulation, sensor-and survey-based mixing matrices produced 188 similar attack rates when adjusted by proportionate mixing expectations (Fig. 4) . We found that two common methods of collecting social contact data, self-274 reported surveys and proximity sensors, recorded qualitatively and quantitatively different 275 individual social mixing behaviour but could still generate similar aggregate age-specific social 276 contact patterns. . https://doi.org/10.1101/2020.07.12.20151696 doi: medRxiv preprint proximity sensors and self-reported surveys were likely to record contacts with different transmission potential, we fitted β for each set of parameters, including the age-specific mixing 18 (EP/N014499/1).

title:
  Age-specific social mixing of school-aged children in a US setting using proximity detecting sensors and contact surveys

abstract:
  Comparisons of the utility and accuracy of methods for measuring social interactions relevant to disease transmission are rare. To increase the evidence base supporting specific methods to measure social interaction, we compared data from self-reported contact surveys and wearable proximity sensors from a cohort of schoolchildren in the Pittsburgh metropolitan area. Although the number and type of contacts recorded by each participant differed between the two methods, we found good correspondence between the two methods in aggregate measures of age-specific interactions. Fewer, but longer, contacts were reported in surveys, relative to the generally short proximal interactions captured by wearable sensors. When adjusted for expectations of proportionate mixing, though, the two methods produced highly similar, assortative age-mixing matrices. These aggregate mixing matrices, when used in simulation, resulted in similar estimates of risk of infection by age. While proximity sensors and survey methods may not be interchangeable for capturing individual contacts, they can generate highly correlated data on age-specific mixing patterns relevant to the dynamics of respiratory virus transmission.


id: cord-339898-ptb6dst8
title: Contact tracing strategies for COVID-19 containment with attenuated physical distancing
author: Bilinski, A.
date: 2020-05-08
txt: ./txt/cord-339898-ptb6dst8.txt
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mime: text/plain
url: http://medrxiv.org/cgi/content/short/2020.05.05.20091280v1?rss=1
doi: 10.1101/2020.05.05.20091280
summary:
  10, 11 Several previous papers have considered the role of contact tracing for containment of COVID-19, [12] [13] [14] [15] but important questions remain about potential impact given uncertainty around the extent of presymptomatic and asymptomatic transmission of SARS-CoV-2 and the efficacy of voluntary isolation and quarantine. We defined scenarios by the fraction of symptomatic cases detected in the community (not linked to a tracked case), the fraction of contacts successfully traced, the isolation and quarantine efficacy among traced but undetected contacts, and whether testing was restricted to those with symptoms or includes all traced contacts ( Table 1) . Given the likely importance of levels of community testing as a prerequisite condition for contact tracing, we conducted a secondary analysis that quantified the combined benefit of scaling up both testing and contact tracing against a counterfactual in which detection of symptomatic cases remains constant at an assumed current fraction of 20%.

abstract:
  Contact tracing has been recommended as a critical component of containment strategies for COVID-19. We used a simple epidemic model to evaluate how contact tracing might enable partial relaxation of current physical distancing restrictions. Testing and tracing coverage need to exceed 50% in order for contact tracing to reduce transmission by at least 10%. With high isolation and quarantine efficacy, contact tracing could reduce overall transmission by >40%, which would allow for substantial loosening of physical distancing measures. Benefits of contact tracing could be enhanced by testing all contacts rather than only those with symptoms and by policies to support high adherence to voluntary isolation and quarantine.


id: cord-340461-hebe5cjb
author: Brooks-Pollock, E.
date: 2020-07-27
txt: ./txt/cord-340461-hebe5cjb.txt
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mime: text/plain
url: https://doi.org/10.1101/2020.07.25.20156471
doi: 10.1101/2020.07.25.20156471
summary:
  Results We demonstrate that pre-collected social contact data, combined with incidence data and Google Community Mobility Reports, is able to provide a time-varying estimate of the reproduction number (R). In this study, we use social contact data [5] , including an additional targeted survey of children, to quantify the impact of re-opening schools on the reproduction number in the UK [9] . In this paper, we demonstrate that a combination of early death counts and social contact data provide sufficient information to estimate the potential impact of combinations of social distancing measures on the reproduction number for COVID-19 in the United Kingdom. Using metrics of adherence to social distancing measures, such as Google mobility or contemporary social contact surveys, it is possible to map the country''s progression across figure 1, and therefore estimate the effect of policy changes on the reproduction number and hence the population attributable fraction of cases due to multiple combined interventions [17] .

title:
  Using social contact data to predict and compare the impact of social distancing policies with implications for school re-opening

abstract:
  Background Social distancing measures, including school closures, are being used to control SARS-CoV-2 transmission in many countries. Once "lockdown" has driven incidence to low levels, selected activities are being permitted. Re-opening schools is a priority because of the welfare and educational impact of closures on children. However, the impact of school re-opening needs to be considered within the context of other measures. Methods We use social contact data from the UK to predict the impact of social distancing policies on the reproduction number. We calibrate our tool to the COVID-19 epidemic in the UK using publicly available death data and Google Community Mobility Reports. We focus on the impact of re-opening schools against a back-drop of wider social distancing easing. Results We demonstrate that pre-collected social contact data, combined with incidence data and Google Community Mobility Reports, is able to provide a time-varying estimate of the reproduction number (R). From an pre-control setting when R=2.7 (95%CI 2.5, 2.9), we estimate that the minimum reproduction number that can be achieved in the UK without limiting household contacts is 0.45 (95%CI:0.41-0.50); in the absence of other changes, preventing leisure contacts has a smaller impact (R=2.0,95%CI:1.8-2.4) than preventing work contacts (R=1.5,95%CI:1.4-1.7). We find that following lockdown (when R=0.7 (95% CI 0.6, 0.8)), opening primary schools in isolation has a modest impact on transmission R=0.83 (95%CI:0.77-0.90) but that high adherence to other measures is needed. Opening secondary schools as well as primary school is predicted to have a larger overall impact (R=0.95,95%CI:0.85-1.07), however transmission could still be controlled with effective contact tracing. Conclusions Our findings suggest that primary school children can return to school without compromising transmission, however other measures, such as social distancing and contract tracing, are required to control transmission if all age groups are to return to school. Our tool provides a mapping from policies to the reproduction number and can be used by policymakers to compare the impact of social-easing measures, dissect mitigation strategies and support careful localized control strategies.


id: cord-341639-a8ig607t
title: Feasibility of controlling 2019-nCoV outbreaks by isolation of cases and contacts
author: Hellewell, Joel
date: 2020-02-11
txt: ./txt/cord-341639-a8ig607t.txt
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mime: text/plain
url: https://doi.org/10.1101/2020.02.08.20021162
doi: 10.1101/2020.02.08.20021162
summary:
  We considered scenarios that varied in: the number of initial cases; the basic reproduction number R0; the delay from symptom onset to isolation; the probability contacts were traced; the proportion of transmission that occurred before symptom onset, and the proportion of subclinical infections. For higher values of R0 and a large initial number of cases, contact tracing and isolation was only potentially feasible when less than 1% of transmission occurred before symptom onset. For example, the severe acute respiratory syndrome (SARS) outbreak that began in Southern China in 2003 was amenable to eventual control through tracing contacts of suspected cases and isolating confirmed cases because the majority of transmission occurred after symptom onset 7 . Figure 4 : The percentage of outbreaks controlled for the baseline scenario (black), and varied number of initial cases (A), time from onset to isolation (B), percentage of transmission before symptoms (C), and proportion of subclinical (asymptomatic) cases (D).

abstract:
  Background: To assess the viability of isolation and contact tracing to control onwards transmission from imported cases of 2019-nCoV. Methods: We developed a stochastic transmission model, parameterised to the 2019-nCoV outbreak. We used the model to quantify the potential effectiveness of contact tracing and isolation of cases at controlling a 2019 nCoV-like pathogen. We considered scenarios that varied in: the number of initial cases; the basic reproduction number R0; the delay from symptom onset to isolation; the probability contacts were traced; the proportion of transmission that occurred before symptom onset, and the proportion of subclinical infections. We assumed isolation prevented all further transmission in the model. Outbreaks were deemed controlled if transmission ended within 12 weeks or before 5000 cases in total. We measured the success of controlling outbreaks using isolation and contact tracing, and quantified the weekly maximum number of cases traced to measure feasibility of public health effort. Findings: While simulated outbreaks starting with only 5 initial cases, R0 of 1.5 and little transmission before symptom onset could be controlled even with low contact tracing probability, the prospects of controlling an outbreak dramatically dropped with the number of initial cases, with higher R0, and with more transmission before symptom onset. Across different initial numbers of cases, the majority of scenarios with an R0 of 1.5 were controllable with under 50% of contacts successfully traced. For R0 of 2.5 and 3.5, more than 70% and 90% of contacts respectively had to be traced to control the majority of outbreaks. The delay between symptom onset and isolation played the largest role in determining whether an outbreak was controllable for lower values of R0. For higher values of R0 and a large initial number of cases, contact tracing and isolation was only potentially feasible when less than 1% of transmission occurred before symptom onset. Interpretation: We found that in most scenarios contact tracing and case isolation alone is unlikely to control a new outbreak of 2019-nCov within three months. The probability of control decreases with longer delays from symptom onset to isolation, fewer cases ascertained by contact tracing, and increasing transmission before symptoms. This model can be modified to reflect updated transmission characteristics and more specific definitions of outbreak control to assess the potential success of local response efforts.


id: cord-346576-gtkx1r4a
title: Privacy versus safety in contact-tracing apps for coronavirus disease 2019
author: Lapolla, Pierfrancesco
date: 2020-07-14
txt: ./txt/cord-346576-gtkx1r4a.txt
cache: ./cache/cord-346576-gtkx1r4a.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/32728475/
doi: 10.1177/2055207620941673
abstract: nan
summary:
  With a view to a gradual exit from lockdown, governments around the world are considering deploying contact-tracing apps to prevent or manage a second wave of coronavirus disease 2019 . 1 Many concerns arise over efficacy, privacy issues and data management by governments or health authorities. A simulation on one million people found that 80% of smartphone users in the UK (56% of the general population) would need to install a contact-tracing app to suppress the epidemic effectively. 2 In Singapore, the first country to deploy a voluntary contact-tracing app (TraceTogether), launched in March, only an estimated 17% of the population installed the app. On 19 April, a letter signed by nearly 300 academics warned that centralised systems can risk surveillance, and suggested that Apple and Google (currently working jointly in developing a contact-tracing app) should consider developing one which uses an opt-in and decentralised system.


id: cord-347217-zxsm18og
title: The need for privacy with public digital contact tracing during the COVID-19 pandemic
author: Bengio, Yoshua
date: 2020-06-02
txt: ./txt/cord-347217-zxsm18og.txt
cache: ./cache/cord-347217-zxsm18og.txt
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mime: text/plain
url: https://www.sciencedirect.com/science/article/pii/S2589750020301333
doi: 10.1016/s2589-7500(20)30133-3
abstract: nan
summary:
  • A non-partisan independent oversight committee with representatives from legal, health, machine-learning, and privacy experts should be established to oversee ongoing development of the application, its information ecosystem, and data governance • Importantly, public representatives must be included in this oversight committee Virtual data acquisition • No identifiable information regarding digital contact trails or personal health information that an individual enters on the application should be shared with other application users or public, private, and governmental agencies • Individual geolocation data should not be stored on a central server and should pass through a rigourous obfuscation protocol to reduce their information content to the bare minimum required for epidemiological and machine-learning modelling • Pseudonymised data should be used to inform machine-learning models, and only these data should be stored centrally on a protected server • Only non-identifiable aggregated data should be shared with public health institutions • The source code of the application and the algorithms used should be made accessible for public scrutiny • Personal identifiable information should be deleted from the device once the pandemic is over


