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Isolation/Quarantine Combined with Social Distancing Contained the Coronavirus Disease 2019 Outbreak in China
19 Pages Posted: 5 May 2020
More...Abstract
Background: To date, the Coronavirus Disease 2019 (COVID-19) pandemic had been successful under control in China. However, the necessity of some non-pharmaceutical interventions (NPIs) remains controversial.
Methods: In this study, we estimated the daily effective reproductive number, Rt, of COVID-19 and seasonal influenza in the years 2010-2020 in China.
Findings: The mean reproductive number, Rt, of COVID-19 before any interventions was 2.43 (95% confidential interval (CI): 2.36-2.50). After Jan 23, 2020, when a set of non-pharmaceutical interventions (NPIs) were implemented, Rt reduced rapidly and remained below 1 after Feb 1, 2020, indicating a successful containment being achieved. Rt of seasonal influenza reduced by 8.9% (95% CI: 6.0%-11.7%) due to the school winter holiday in the epidemiological years 2010-2018. In the epidemiological year 2019, due to the NPIs implemented to prevent COVID-19 pandemic, Rt of seasonal influenza reduced by 34.3% (95% CI: 32.7%-35.2%). By assuming a similar mode and efficiency of NPIs against influenza and COVID-19, we concluded that social distancing and isolation/quarantine alone would lead to a 34% (95% CI: 33%-35%) and 50% (95% CI: 47%-52%) reduction of the COVID-19 transmissibility, respectively. Given that the typical reproductive number of COVID-19 is 2-3, either social distancing or isolation/quarantine alone could not lead to the reproductive number below the critical transmission threshold (Rt =1). Both interventions implementation together is required to contain the COVID-19 pandemic globally before the effective vaccine becomes available.
Interpretation: It has been proved that asymptomatic infectors could transmit COVID-19, so traditional isolation/quarantine measure is not enough to contain COVID-19.
Funding Statement: This project was supported by National Key R&D Program of China (2020YFC0840900), Shenzhen Science and Technology Program (Grant No. KQTD20180411143323605), the grants from Zhejiang Natural Science Foundation (Grant No. LQ20H260009).
Declaration of Interests: All authors declare no competing interests.
Keywords: Coronavirus Disease 2019, isolation/quarantine, social distancing, efficiency
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