key: cord-0806382-d92pd744
authors: Chen, L.-S.; Yen, M.-F.; Lai, C.-C.; Hsu, C.-Y.; Chen, H.-H.
title: Easing social distancing index after COVID-19 pandemic
date: 2020-06-12
journal: nan
DOI: 10.1101/2020.06.11.20128165
sha: 5fd74b3e0f398b375a0ddf8fb0caf150f0416e74
doc_id: 806382
cord_uid: d92pd744

Abstract Context Easing social distancing (ESD) is a global public health issue in post-pandemic period of COVID-19 and requires a simple index for real time assessment. Objective We aimed to develop a simple index for ESD to quantify the impacts of social distancing for reducing confirmed infected cases, optimal triage and care of patients for recovery, and critical care capacity for reducing death from COVID-19. Design, Setting, and Participants Data on the retrospective cohort of 185 countries with reported numbers on confirmed cases, recovery, and death from COVID-19 were retrieved from publicity available repository. Up to May 31, a total of 5,844,136 confirmed cases, 2,639,961 recovered, and 327,487 deaths were reported globally. Main Outcome Measures The ESD index measured by cumulative number of COVID-19 cases and recovery and case-fatality rate. Results We developed a simple index for the guidance of easing social distancing (ESD). If the ESD index is less than 1, ESD would be considered. The global ESD index declined from 3.87 at peak in March to 1.35 by the end of May, consisting of 56.76% countries/regions (105/185) with the ESD lower than one. Conclusion and Relevance This simple ESD index provides a quantitative assessment on whether and when to ease social distancing from local to global community.

While border controls and social distancing have been executed since the beginning of the Coronavirus disease 2019 (COVID-19) pandemic [1] [2] [3] [4] it is time to ponder over how to ease social distancing in the post-pandemic period with real time assessment 5 as reviving economic business and normal social activities have been urgently needed.

Though there are six criteria for countries while considering de-escalation by reversing restrictions or lockdown 6 , it is still unclear whether and when to implement the reopening policy. It is insufficient to merely consider the force of the spread of COVID-19. [2] [3] [4] [7] [8] [9] [10] [11] One has to consider the optimal allocation of COVID-19 with an efficient triage system to accelerate the rate of recovery from hospitalization or selfisolation and also take into account critical care capacity to avert death from COVID-19. To quantify the impacts of these three factors, a simple ESD index was developed for health decision-makers to do real-time assessment of COVID-19 at global, country, region, and community level.

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The data for analysis were derived from the web-based real-time GitHub repository created by the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University. 12 CSSE operates daily updates upon publicly available data, including confirmed cases, recovered cases, and deaths from multiple sources. A total of 188 countries have reported confirmed COVID-19 cases (including presumptive positive cases and probable cases) at country and region level that is aligned with WHO situation reports. 13 ESD is the ratio of cumulative confirmed cases to cumulative recovered patients without dying from COVID-19 that is captured by (1-case-fatality (f)) minus one during a fixed time period. The reason for subtracting one is that in an ideal scenario the aforementioned ratio would reach 1 when all confirmed cases have been recovered . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)

The copyright holder for this preprint this version posted June 12, 2020. . https://doi.org/10.1101/2020.06.11.20128165 doi: medRxiv preprint without death (case-fatality rate=0) and therefore ESD would approach zero, suggesting the region has a full recovery after the outbreak of COVID-19 and may return to the normal status.

However, it is impracticable to ease social distancing until the value of ESD reaches to 0. One has to consider the balance between the spread of COVID-19, the rate of recovery, and critical care capacity. The first element is to capture the information on the force in relation to the spread of COVID-19 after the implementation of social distancing that is often modelled by reproductive number.

The second element is dependent on whether health care systems have the capacity of offering hospitalization based on efficient triage of COVID-19 patients. The third one is determined by critical care capacity that can stop the progression from acute respiratory distress syndrome (ARDS) to subsequent deaths. If the value of ESD index is larger than 1 it is still necessary to maintain social distancing because the rate of the spread of COVID-19 still outweighs the affordable capacity of hospitalization and critical care. If it is lower than 1 easing social distancing (ESD) can be considered.

The degree of ESD lower than 1 is assessed by the inverse of the decile of ESD index form the lowest percentile (0.1) to the highest percentile (1). The multinomial distribution using the reported number of confirmed cases, recovery, and death in conjunction with Bayesian Markov Chain Monte Carlo method was used for the . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted June 12, 2020. . https://doi.org/10.1101/2020.06.11.20128165 doi: medRxiv preprint 6 derivation of 95% credible interval (CI) for the ESD index.

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The copyright holder for this preprint this version posted June 12, 2020. . https://doi.org/10.1101/2020.06.11.20128165 doi: medRxiv preprint According to the decile of the ESD index for each of two categories (≥ 1 and <1), is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted June 12, 2020. . https://doi.org/10.1101/2020.06.11.20128165 doi: medRxiv preprint 8 1.9 (n=10), 2-2.4 (n=4), 2.5-2.9 (n=5) and 3+ (n=35).

The ESD index can be adapted to different kinds of scenarios featuring with differential influences of three elements.

Countries and regions show a low ESD index such as Iceland and Taiwan had high recovery rate (Iceland: 99%, Taiwan: 96%) and low case-fatality (Iceland: 0.6%, Taiwan: 1.6%), both indicate that the spread of COVID-19 has been contained and both the patient triage system and critical care capacity were affordable to meet the needs for COVID-19 cases during the pandemic. For countries such as Germany (ESD index: 0.163; 95% CI: 0.160-0.166), a moderate case-fatality rate (4.7%) was compensated by the high recovery rate (90%) through early detection followed by efficient patient triage and high capacity of hospitalization.

Countries with high ESD index such as France (ESD: 2.257; 95% CI: 2.235 -2.278) were attributed to high case-fatality rate mainly resulting from insufficient capacity of critical care. The high ESD index was, to a greater extent, due to 15.2% case-fatality rate (around 2.7 times the average worldwide) and, to a lesser extent, due to modest recovery rate (36.2%, around 0.8 of the average worldwide).

The impact of high transmission of SARS-COV-2 and low recovery rate (17.8%)

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The copyright holder for this preprint this version posted June 12, 2020. . https://doi.org/10.1101/2020.06.11.20128165 doi: medRxiv preprint 9 would result in extremely higher ESD demonstrated by New York State (ESD: 5.011; 95% CI: 4.967-5.053) even though the case-fatality rate (6.4%) was comparable to the average worldwide.

The ESD index can be also applied to evaluating whether social distancing has to be re-executed. Using South Korea as an example, although the overall ESD till the end of April was 0.22, the ESD indices from May 1 up to May 16 and May 31 were estimated as 2.39 and 4.93, respectively, indicating that the outbreak was re-emerging and might call for re-strengthening social distancing measures.

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In summary, a simple index for easing social distancing was developed to aid health policy-makers in the assessment of whether and when to ease social distancing in post-pandemic period from local to global community.

. CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted June 12, 2020. . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)

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