key: cord-0963186-o4busczc
authors: Chen, Simiao; Chen, Qiushi; Yang, Juntao; Lin, Lin; Li, Linye; Jiao, Lirui; Geldsetzer, Pascal; Wang, Chen; Wilder-Smith, Annelies; Bärnighausen, Till
title: Positive impact of facility-based isolation of mild COVID-19 cases on effectively curbing the pandemic: a mathematical modelling study
date: 2020-12-03
journal: J Travel Med
DOI: 10.1093/jtm/taaa226
sha: bd4919c3be2fe4a4310daec8aceca842f28cd016
doc_id: 963186
cord_uid: o4busczc

BACKGROUND: In many countries, patients with mild coronavirus disease 2019 (COVID-19) are told to self-isolate at home, but imperfect compliance and shared living space with uninfected people limit the effectiveness of home-based isolation. We aim to examine the impact of facility-based isolation compared to self-isolation at home on the continuing epidemic in the United States. METHODS: We developed a compartment model to simulate the dynamic transmission of COVID-19 and calibrated it to key epidemic measures in the United States from March to September. We simulated facility-based isolation strategies with various capacities and starting times under different diagnosis rates. The primary model outcomes included the reduction of new infections and deaths over two months from October onwards. We further explored different effects of facility-based isolation under different epidemic burdens by major US Census Regions, and performed sensitivity analyses by varying key model assumptions and parameters. RESULTS: We projected that facility-based isolation with moderate capacity of 5 beds per 10 000 total population could avert 4.17 (95% Credible Interval 1.65–7.11) million new infections and 16 000 (8000-23 000) deaths in two months compared with home-based isolation, equivalent to relative reductions of 57% (44–61%) in new infections and 37% (27–40%) in deaths. Facility-based isolation with high capacity of 10 beds per 10 000 population would achieve greater reduction of 76% (62–84%) in new infections and 52% (37–64%) in deaths when supported by the expanded testing with a 20% daily diagnosis rate. Delays in implementation would substantially reduce the impact of facility-based isolation. The effective capacity and the impact of facility-based isolation varied by epidemic stage across regions. CONCLUSION: Timely facility-based isolation for mild COVID-19 cases could substantially reduce the number of new infections and effectively curb the continuing epidemic compared to home-based isolation. The local epidemic burden should determine the effective scale of facility-based isolation strategies.

The worldwide death toll from coronavirus disease 2019 (COVID-19) is staggering. One of the most critical decisions in this current phase of the pandemicas well as for long-term control strategiesis how to isolate and manage patients with asymptomatic, mild, or moderate COVID-19. 1, 2 As the majority of COVID-19 cases have a mild clinical course, effective strategies are needed to isolate such cases.

Isolation of people with mild COVID-19 is particularly important because they tend to be more active and thus have more contacts with other people compared to patients with severe COVID-19 whose symptoms impede their mobility and often lead to isolation in hospitals. Patients with mild COVID-19 may also have higher viral load and thus could be more infectious per contact than patients with more severe In most countries, hospital bed capacity is insufficient to isolate all patients as the need for isolation increases during epidemic surges. Indeed, many countries, such as the United States and the United Kingdom, have built shelter hospitals to ensure that COVID-19 patients in recovery and other patients who do not need intensive or complex treatments receive adequate care. 4 ,5 Yet, in general, these countries have chosen to isolate patients with mild to moderate COVID-19 in their homes. 6 Home-based isolation, however, has several important limitations. For one, home-based isolation is not effective in preventing transmissions within households. In China, before the implementation of facilitybased isolation, more than half of COVID-19 patients had at least one family member with the disease, and 75-80% of all clustered infections occurred within families. 7, 8 In New York City, 66% of COVID-19 cases were people who had stayed in their homes, 9 suggesting high rates of intra-family transmission of COVID-19. Furthermore, it is difficult to achieve high compliance with home-based isolation. 10 Studies have shown that home-based isolation decreases non-household contacts of patients by only 10% to 50%. [11] [12] [13] A rigorous review concluded that 46-66% of transmission is household-based (using the standard formula for attributable fraction). 14 An alternative strategy to home-based isolation is facility-based isolation. The facility-based isolation model is exemplified by several Asian countries such as China, Singapore, South Korea and Vietnam. [15] [16] [17] [18] [19] [20] [21] [22] One example is the Fangcang shelter hospitals that were a major component of COVID-19 control measures in Wuhan, China, the original epicenter of the epidemic. 15 These hospitals were rapidly converted from existing public facilities and served to simultaneously isolate and care for patients with mild to moderate COVID-19. 15 In Singapore, asymptomatic and mild COVID-19 patients are isolated in community care facilities, which were modeled after the Fangcang shelter hospitals in China. 18 South

Korea and Vietnam also adopted this approach. In South Korea, patients with severe COVID-19 were sent to hospitals, while those with mild COVID-19 checked into isolation units at converted community facilities and corporate training facilities. 16, 17 In Vietnam, all COVID-19 patients, including the asymptomatic cases, were hospitalized. 20, 21 Recently, Hong Kong rapidly converted an exhibition center into a facility for isolating and treating patients with mild COVID-19, as the city experienced surging COVID-19 case numbers and a hospital bed shortage. 19 As countries emerging from COVID-19 lockdowns, they gradually reopened the borders and resumed air traffic. To prevent import-related COVID-19 infections, many countries have also adopted facility-based centralized quarantine and isolation strategy among travelers. For example, all travelers will be quarantined in centralized quarantine centers in China. 23 In Singapore, all travelers from high-risk countries will be transported directly from the airport to the hotels for facility-based quarantine and isolation and are not allowed to leave their individual rooms. 24 Even though some of the travelers may not be tested positive at the airport, they may have already contracted the virus but in the latent or presymptomatic stage. Facility-based quarantine and isolation among travelers, accompanied with expanded testing, can effectively identify and diagnose infected cases in a timely manner. 25

Several empirical studies have shown that facility-based isolation of asymptomatic, mild and moderate cases is associated with reduced COVID-19 daily reproduction number, infections, and mortality. [25] [26] [27] [28] A recent study reconstructed the full transmission dynamics of COVID-19 in Wuhan and found that the control efforts based on facility-based isolation and quarantine averted about 70% of infections in total. 29 Another modeling study also showed that facility-based isolation could effectively avert 37% more infections than home-based isolation in the epidemic setting of Singapore. 30 It remains unclear, however, how epidemic control outcomes would be affected by different implementation designs of facility-based isolation and epidemic factors. In this study, we aimed to examine the potential impact of facility-based isolation at different scales and starting times, compared to home-based isolation. We based our analysis on the continuing COVID-19 epidemic in the United States, which currently has the highest COVID-19 burden in the world. 31 Using a mathematical model calibrated to the recently reported epidemic metrics at national and regional levels in the United States, we projected the reductions in new infections and deaths due to facility-based isolation with various designs compared to home-based isolation.

We used a compartment model, a common modeling approach to project temporal trends and to estimate the impact of interventions on infectious disease transmission, 32, 33 to simulate the epidemic trajectory of the COVID-19 epidemic in the United States. We extended the classic Susceptible-Exposed-Infectious-Removed (SEIR) model by incorporating pre-symptomatic, asymptomatic and undiagnosed infections ( Figure S1 ). We further differentiated the diagnosed COVID- 19 

June and surpassed the outbreak's first explosion in April. 39 The number of daily cases has decreased substantially since the second peak in July, but the decreasing trend appears to slow down since September. To capture these temporal changes in disease transmission, we used a cubic spline function to approximate the transmission rate function over time, with 13 knots spread over the 6-month time span from mid-March to mid-September (Supplement S1).

We assumed the incubation period from infection to symptom onset to be 5.2 days, 44 and a presymptomatic infectious period of 2.3 days to account for transmissions that occur before symptom onset. 29 Pre-symptomatic and asymptomatic cases are essential to disease transmission, but the estimates of their contributions have remained highly uncertain. We followed the current best estimate of the Centers for Disease Control and Prevention COVID-19 pandemic planning scenarios 45 and assumed that 40% of infections were asymptomatic and the infectiousness of pre-symptomatic and asymptomatic cases were 75% that of the symptomatic ones. The mean time interval from symptom onset to confirmation or self-isolation at home was 2.6 days 46 and the overall infection duration since symptom onset was estimated to be 7 days. 47, 48 Patients with mild to moderate COVID-19 were assumed to be in home-based isolation after diagnosis.

However, due to imperfect effectiveness and compliance of isolation at home depending on housing conditions, home-based isolation does not completely stop contact and transmission. We assumed that during home-based isolation, the social contact rate was reduced by 50%, based on existing evidence

showing reductions of the social contact rate between 10% and 50% 11, 13 and in line with the assumption made in a previous mathematical modelling study. 12 Early evidence during the epidemic showed that 19% of patients had severe to critical COVID-19 upon diagnosis. 34, 49 As increasing proportions of young and healthy people become infected and receive COVID-19 tests, the case-severity ratio is likely to decline over time. [50] [51] [52] The mortality rate of patients

10 with severe conditions may also become lower due to more effective treatment protocols than those implemented in early epidemic stage. We therefore allowed case-severity ratio and mortality rate to decline in our model with the decreasing rates determined via model calibration. For severe cases, we assumed that the average time from hospitalization to recovery was 13 days based on empirical evidence. 34, 53, 54 Our data source for model calibration included the daily new confirmed cases, COVID-19 related deaths, and current hospitalizations in the United States from The COVID Tracking Project. 39 The values of the knots for the transmission rate spline function, the rates of decrease for the case-severity ratio and mortality rate were calibrated to the above key epidemic metrics using the Metropolis-Hastings Markov chain Monte Carlo (MCMC) algorithm. 55 

Our objective was to estimate the impact of facility-based isolation of patients with mild to moderate COVID-19 compared to the status-quo policy of home-based isolation. The primary outcomes were the number of new infections and deaths over two months (60 days) since October for each isolation strategy.

We examined two critical design factors in facility-based isolation: the capacity and the starting time of facility-based isolation. In particular, we considered three different levels of capacity for facility-based isolation relative to the size of the total population: (1) a moderate capacity of 5 beds per 10,000 population (i.e., facilities can isolate at most 5 patients with mild to moderate COVID-19 per total 10,000 population, while mild to moderate cases in excess to this population ratio remain in home-based

(2) a high capacity of 10 beds per 10,000 population, which represents a scenario comparable to the scale of Fangcang shelter hospitals in the city of Wuhan during February and March 2020, 15 where facility-based isolation was first proposed and implemented; and (3) a low capacity of 2.5 beds per 10,000

population. Furthermore, we projected the outcomes of implementing facility-based isolation with a moderate capacity (i.e., 5 beds per 10,000 population) at different starting times relative to the epidemic outbreak: (1) immediately, (2) after 14 days, and (3) after 28 days since the start of our model projections.

Another critical factor that could influence disease transmission and thus the impact of isolation strategies is whether infected individuals can be effectively identified and diagnosed in a timely manner. This could be improved by expanded testing among high-risk individuals, through additional public health measures such as contact tracing, monitoring, frequent screening, and quarantine for suspected cases and close contacts. To examine potential benefits of the expanded testing, we further evaluated each isolation strategy under additional diagnosis of 10% and 20% per day, respectively, among asymptomatic, presymptomatic, and symptomatic individuals who self-isolate at home.

The COVID-19 epidemic has demonstrated substantial geographic heterogeneity within the United States.

With different epidemic control efforts, levels of compliance to reducing contact, and timelines of reopening the economy after an initial lockdown, 57-59 the different regions of the United States have exhibited widely varied courses of the epidemic and are currently in different epidemic stages. 38,39,57 To further explore the differential impact of facility-based isolation and its roles at different epidemic stages, we performed regional analyses for the 4 US Census Regions: West, Midwest, South, and Northeast. 60 We recalibrated the model for each region and projected the epidemic under the same set of isolation strategies and assumptions as the base case national analysis.

We conducted several sensitivity analyses to test the robustness of our results under different parameter assumptions. In particular, we recalibrated our model with the more optimistic assumption that homebased isolation reduced social contacts and transmission rates by 70% and 90%, respectively, compared to no home-based isolation. We also performed analyses that considered a longer duration of infectious period of 10 days, 45 

The funders of the study had no role in study design, data collection, data analysis, data interpretation, or writing of the article.

Our model projected that in the status-quo scenario, where all patients with mild to moderate COVID-19

self-isolated at home, the cumulative number of confirmed COVID-19 cases would increase from 7.27 (95% CrI 7.06-7.44) million to 10.84 (95% CrI 9.07-13.73) million within two months from the beginning of October (Figure 1) . (95% CrI 44%-61%) compared to the home-based isolation scenario (Figure 2, Table S2 ). Facility-based isolation at this capacity level reduced the number of deaths within two months to 26,000 (95% CrI 19,000-44,000), resulting in 16,000 (95% CrI 8,000-23,000) deaths averted, which is equivalent to a 37%

(95% CrI 27%-40%) relative reduction.

A higher capacity of facility-based isolation would potentially avert more infections and deaths, depending on its relative scale compared with the population confirmed with mild to moderate conditions.

Reducing the capacity to 2.5 beds per 10,000 population resulted in a smaller reduction in new infections by 32% (95% CrI 22%-42%) and in deaths by 20% (95% CrI 16%-23%) within 2 months, which were equivalent to 2.35 (95% CrI 1.40-3.50) million new infections and 8,000 (95% CrI 6,000-11,000) deaths averted in total (Figure 2, Table S2 ).

We found that expanded testing could further boost the impact of facility-based isolation strategies. Under the expanded testing with a diagnosis rate of 20% per day, facility isolation of moderate capacity achieved higher epidemic impact by averting 69% (95% CrI 56%-72%) of new infections and 45% (95% CrI 36%-48%) of deaths, equivalent to 5.01 (95% CrI 2.11-8.81) million new infections and 19,000 (95% CrI 10,000-29,000) deaths averted, respectively (Figure 2, Table S2 ). Increasing diagnosis rate through expanded testing would also enable the facility isolation strategy to scale up the impact through increasing its capacity. Facility isolation with the high capacity (10 beds per 10,000 persons) would further increase the reduction to 76% (95% CrI 62%-84%) for new infections and 52% (95% CrI 37%-64%) for deaths, under the expanded testing with 20% per day diagnosis rate.

We next examined how the starting time of facility-based isolation affects its impact on new infections and deaths. We found that delays in starting isolating patients with mild to moderate COVID-19 in facilities reduced the impact of facility-based isolation (Figure 3) . If facility-based isolation were implemented two weeks after the beginning of the model projection, the number of new infections in the next two months would decrease to 4.57 (95% CrI 2.93-11.39) million, equivalent to a 37% (95% CrI 24%-40%) relative reduction compared to the status-quo scenario ( Table S3 ). This relative reduction is substantially lower than that for the immediate implementation scenario (which led to a 57% reduction).

With the longer implementation delay of 4 weeks, the impact of facility-based isolation would be even lower: a 19% (95% CrI 11%-23%) relative reduction in new infections. Delay in implementing facilitybased isolation also reduced the impact on averting deaths: a 2-week delay resulted in relative reduction of deaths of 20% (95% CrI 14%-21%) and a 4-week delay resulted in a 7% (95% CrI 5%-9%) relative reduction. Within each stratum of implementation time, facility-based isolation was increasingly effective in reducing new infections and deaths when the time from infection to diagnosis was shortened through expanded testing (Figures 2 and 4) .

In our regional analysis, we found that the effects of facility-based isolation differed by region, depending on the stage of the regional epidemic (Table S4, Figure S4 ). In the Northeast of the United States, where epidemic spread has remained low but been rising slowly, even facility-based isolation with low capacity can avert 60% of new infectionsan impact that is sufficient to effectively contain the epidemic. In the Midwest of the United States, where the number of daily cases is growing rapidly, facility-based isolation strategies could reduce new infections in two months by 37% (95% CrI 24%-50%) new infections under a moderate capacity, slowing down the increasing trend, or would bring the daily cases down to a decreasing trend with a high capacity. In the West and South of the United States, with the number of daily cases beginning to flare-up following the decreasing trend since the peak in mid-July, facility-based isolation with a moderate capacity would reduce new infections up to 59% (95% CrI 48%-65%) and 54%

15 (95% CrI 42%-57%), respectively, showing the potential of reverting the growing epidemic to a decreasing trend. These comparison across regions implies that the impact of facility-based isolation may vary by the epidemic stage within each region and that the effective capacity of facility-based isolation should be adapted to the epidemic burden accordingly.

To examine the robustness of our results, we performed additional sensitivity analyses on several model parameters that were based on assumptions or partial data. Our results showed that when home-based isolation were highly effective, facility-based isolation would result in fewer relative reductions of new infections (Table S5) . On the other hand, the impact of facility-based isolation became much less sensitive to the effectiveness of home-based isolation when there was expanded testing, because it allows the facility-based isolation to effectively prevent the disease transmission caused by undiagnosed infections (i.e., pre-symptomatic and asymptomatic cases). Other factors showed only modest effects on our results compared to the base case.

Compared to home-based isolation, facility-based isolation with a moderate capacity for patients with mild to moderate COVID-19 was projected to avert 4. 

The overall impact of facility-based isolation in the United States hides substantial regional differences.

For regions with low epidemic burdens, such as the Northeast of the United States, facility-based isolation with low capacity is adequate to effectively maintain the epidemic under control despite the new cases have been rising since September. In contrast, for regions with high epidemic burdens and the continuing growth, such as the Midwest of the United States, facility-based isolation would require a high capacity to effectively revert the increasing trend and reduce the epidemic burden. The capacity for facility-based isolation thus needs to be adapted to local epidemic burdens to ensure that the potential benefits of this strategy are reaped.

States compared to home-based isolation is consistent with a recent study estimating the impact of facility-based isolation for Singapore. 30 Recent evidence show that countries without facility-based isolation for mild COVID-19 patients such as Germany, Israel, Australia, and Japan did not contain the outbreak to the extent that those countries with facility-based isolation did. Israel and Germany have announced a second lockdown. 61 Both Australia and Japan saw flare-ups during August, due to low compliance and high rate of intra-family transmissions. 25, 62 Without facility-based isolation for all COVID-19 patients including mild ones and other supportive public health interventions such as massive testing, contact tracing and quarantine, social distancing and lock-down measures alone cannot completely suppress the epidemic-once a closure period ends and the economy reopens, second-waves are likely to occur. 63 One implication of these results is that the United States could consider re-purposing the emergency field hospitals that were built in several citiesto offer facility-based isolation to people with mild to moderate COVID-19. 64 These existing field hospitals in the United States and other highincome countries served primarily other functions, in particular providing overflow bed capacity, which hospitals could use to transfer COVID-19 patients who had needed intensive and complex care but had sufficiently recovered to be treated at lower levels of care. 65 Another purpose these existing field hospitals

17 served was to provide care for people needing hospitalization for COVID-19-unrelated healthcare needs, who could not be offered beds in traditional hospitals as the number of COVID-19 patients in hospitals swelled. 65 The focus on these two functions resulted in under-utilization of the existing field hospitals, which in the United States are estimated to have cost more than $660 million to build. 66 can relieve pressure from traditional hospitals during epidemic surges; 15, 71, 72 and, second, facility-based isolation will avert new infections and thus fundamentally reduce the need for hospital capacity.

In this context, we note that we have only modeled the isolation and triage functions of facility-based isolation and its overall epidemic impact in the community, as illustrated by the Fangcang shelter hospitals in China, 15 but have not captured other functions that facility-based isolation can fulfill. These other functionsincluding frequent disease monitoring, rapid referral to higher level facilities through pre-organized referral processes, relieving burden of secondary and tertiary hospitals with limited healthcare resources, and strict discharge criteria ensuring patients are not infectious 6,15,73,74likely provide additional health benefits compared to home-based isolation. Taking all benefits into consideration and the relatively low costs in setting up and managing mild patients, facility-based isolation is also likely to be highly cost-effective. 15 On the other hand, when isolated in the facility, patients are cut off from their families and social support networks and may find it harder to work

18 remotely in shelter hospital environment than at home. Further empirical research is needed to identify those patients who might find facility-based isolation desirable or at least acceptablefor instance, those who fear they might infect their family or community members in home-based isolation. 75, 76 Cultural differences and ethical concerns could also be the barriers for the wide adoption of facility-based isolation in Western countries. Countries and communities will likely need to carefully tailor policies and legislation supporting facility-based isolation to public sentiment, as well as support offers of facilitybased isolation, at least on voluntary basis with strong communication and public engagement strategies.

Finally, the design of facilities for isolating patients with mild to moderate COVID-19 can ensure that they are desirable places for care and recoveryfor instance, by maximizing patients privacy, amenities, and access to work space within the physical constraints of the facilities. 15 Our study has several limitations. First, we only estimated the epidemic impact of facility-based isolation, but did not quantify impacts on social and economic outcomes. Future research should measure the costeffectiveness of facility-based isolation in reducing COVID-19 epidemic spread, as well as the impact on patients' economic activity and social functioning. Second, we did not explicitly formulate the operational processes such as admission, transfer, and discharge for the facility-based isolation. We assumed that infected individuals could be isolated immediately as long as the capacity was not fully utilized and would be removed once they recovered, implying that our model may have overestimated the throughput rate of the actual facility-based isolation because of possible administrative delays or the longer required length of stay in practical operations. Therefore, the capacity parameter in our model can be interpreted as the scale of population under complete isolation, to inform the minimal physical capacity needed for isolation facilities. Third, although we performed the regional analysis to evaluate the impact of facilitybased isolation at the US census region level, there still exists substantial heterogeneity in the epidemic burden at smaller geographic scales in the United States. Our regional analysis is not to provide facility-

19 based isolation policy recommendation by census region, but to demonstrate the differential values of the facility-based isolation strategy in different epidemic contexts. The most effective scale and capacity of facility-based isolation should be determined based on the epidemic burden at the local level. Lastly, our model projection was based on transmission patterns that were calibrated to the data prior to October, when this analysis was performed and was underestimating the most recent epidemic trends in the United

States. It does not undermine the value of our results, because our analysis focused on evaluating the impact of facility-based isolation on the epidemic, rather than only forecasting the future epidemic trajectories; the number of infections averted by facility-based isolation were expected to be even higher when the epidemic grows faster.

In summary, taking the United States as an example, we showed that facility-based isolation has a great potential to effectively mitigate the spread of the COVID-19 pandemic. By completely isolating patients with mild to moderate COVID-19 in facilities-rather than incompletely isolating patients in their homes -over a half of new infections within two months could be averted given the current epidemic burden in the United States. Expanded testing could further reinforce the effects of facility-based isolation by identifying undiagnosed infections and cutting off transmissions in a more timely manner. The local epidemic burden should be taken into account to determine the effective scale of facility-based isolation in communities.

All authors declare no competing interests. Note: The percentage of new infections averted was estimated by comparing the projected number of new infections (including both diagnosed and undiagnosed) during October and November, 2020, under homebased isolation scenario versus the facility-based isolation with different capacities. Expanded testing indicates additional diagnosis of 10% and 20% per day, respectively, among asymptomatic, presymptomatic, and symptomatic individuals who self-isolate at home. Note: The percentage of new infections averted was estimated by comparing the projected number of new infections (including both diagnosed and undiagnosed) during October and November, 2020, under homebased isolation scenario versus the facility-based isolation scenarios with different starting times. Expanded testing of 10% and 20% indicates additional diagnosis of 10% and 20% per day, respectively, among asymptomatic, pre-symptomatic, and symptomatic individuals who self-isolate at home.

Critical supply shortages-the need for ventilators and personal protective equipment during the Covid-19 pandemic

Fair allocation of scarce medical resources in the time of Covid-19

Temporal dynamics in viral shedding and transmissibility of COVID

Javits Center still largely empty of NYC coronavirus patients

Field hospitals are being dismantled after doctors hardly used them to treat coronavirus patients

From containment to mitigation of COVID-19 in the US

Characteristics of COVID-19 infection in Beijing

Report of the WHO-China joint mission on coronavirus disease 2019 (COVID-19)

Cuomo says it's 'shocking' most new coronavirus hospitalizations are people who had been staying home

COVID-19 nursing home patients not isolated-7 dead

Effectiveness of interventions to reduce contact rates during a simulated influenza pandemic

Impact of non-pharmaceutical interventions (NPIs) to reduce COVID-19 mortality and healthcare demand

Response Team

The impact of behavioral interventions on co-infection dynamics: an exploration of the effects of home isolation

The engines of SARS-CoV-2 spread

Fangcang shelter hospitals: a novel concept for responding to public health emergencies

Repurposing and reshaping of hospitals during the COVID-19 outbreak in South Korea

Managing COVID-19 in a

China Daily. Mainland medics banking on experience to help HK fight COVID-19

COVID-19 -What do we know about the situation in Vietnam

Epidemic: Experiences from Vietnam

COVID-19 control in China during mass population movements at New Year. The

Centralized medical quarantine for imported COVID-19 in Shanghai

Reducing onward spread of COVID-19 from imported cases: quarantine and 'stay at home'measures for travellers and returning residents to Singapore

Reduction in effective reproduction number of COVID-19 is higher in countries employing active case detection with prompt isolation

Effects of Fang Cang shelter hospitals on the reduction of COVID-19 new cases in Wuhan: an interrupted time series analysis

The effects of "Fangcang, Huoshenshan, and Leishenshan" hospitals and environmental factors on the mortality of COVID-19

Reconstruction of the full transmission dynamics of COVID-19 in Wuhan

Institutional, not home-based, isolation could contain the COVID-19 outbreak

An interactive web-based dashboard to track COVID-19 in real time

Mathematical epidemiology

measures on the growth rate of confirmed COVID-19 cases across the United States

Early transmission dynamics in Wuhan, China, of novel coronavirusinfected pneumonia

COVID-19 pandemic planning scenarios

Effectiveness of isolation, testing, contact tracing and physical distancing on reducing transmission of SARS-CoV-2 in different settings

The effect of control strategies to reduce social mixing on outcomes of the COVID-19 epidemic in Wuhan, China: a modelling study. The Lancet Public Health

Effects of non-pharmaceutical interventions on COVID-19 cases, deaths, and demand for hospital services in the UK: a modelling study. The Lancet Public Health

Severe outcomes among patients with coronavirus disease

The COVID Tracking Project. Why changing COVID-19 demographics in the US make death trends harder to understand

Laboratory-confirmed COVID-19-associated hospitalizations, preliminary weekly rates as of

The contribution of the age distribution of cases to COVID-19 case fatality across countries: a 9-country demographic study

Risk factors associated with acute respiratory distress syndrome and death in patients with coronavirus disease 2019 pneumonia in Wuhan, China

Clinical characteristics of coronavirus disease 2019 in China

Bayesian data analysis

The COVID Tracking Project

The New York Times. See how all 50 states are reopening (and closing again)

The Washington Post. Where states reopened and cases spiked after the U.S. shutdown

All 50 states have begun to reopen. See what that means for your state

United States Census Bureau. 2010 census regions and divisions of the United States

Institutional versus home isolation to curb the COVID-19 outbreak-Authors' reply. The Lancet

Forced Isolation May Be the Only Way to Stop Resurgence of Virus

Buying time for an effective epidemic response: The impact of a public holiday for outbreak control on COVID-19 epidemic spread

Repurposing facilities for isolation and management of mild COVID-19 cases: Manila: WHO Regional Office for the Western Pacific

Too little or too much? Missing the Goldilocks zone of hospital capacity during covid-19

field hospitals stand down, most without treating any COVID-19 patients

Six months into Covid, England's quarantine programme is still a mess

Nightingale hospitals largely empty as NHS weathers the storm

CNBC. Nearly 90% of the US Navy hospital ship in New York is empty amid coronavirus fight

Why NYC's largest emergency hospital is empty during COVID-19

Sustaining containment of COVID-19 in China

The COVID-19 catastrophe: what's gone wrong and how to stop it happening again

Covid-19: a remote assessment in primary care

Duration of SARS-CoV-2 RNA detection in COVID-19

2020 -an interval-censored survival analysis

I love you, but I don't want to get you sick

Coronavirus: Health minister Nadine Dorries tests positive