The COVID-19 outbreak in Sichuan, China: Epidemiology and impact of interventions

PLoS Comput Biol. 2020 Dec 28;16(12):e1008467. doi: 10.1371/journal.pcbi.1008467. eCollection 2020 Dec.

Abstract

In January 2020, a COVID-19 outbreak was detected in Sichuan Province of China. Six weeks later, the outbreak was successfully contained. The aim of this work is to characterize the epidemiology of the Sichuan outbreak and estimate the impact of interventions in limiting SARS-CoV-2 transmission. We analyzed patient records for all laboratory-confirmed cases reported in the province for the period of January 21 to March 16, 2020. To estimate the basic and daily reproduction numbers, we used a Bayesian framework. In addition, we estimated the number of cases averted by the implemented control strategies. The outbreak resulted in 539 confirmed cases, lasted less than two months, and no further local transmission was detected after February 27. The median age of local cases was 8 years older than that of imported cases. We estimated R0 at 2.4 (95% CI: 1.6-3.7). The epidemic was self-sustained for about 3 weeks before going below the epidemic threshold 3 days after the declaration of a public health emergency by Sichuan authorities. Our findings indicate that, were the control measures be adopted four weeks later, the epidemic could have lasted 49 days longer (95% CI: 31-68 days), causing 9,216 more cases (95% CI: 1,317-25,545).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • COVID-19 / epidemiology*
  • COVID-19 / prevention & control*
  • COVID-19 / virology
  • China / epidemiology
  • Disease Outbreaks*
  • Female
  • Humans
  • Male
  • SARS-CoV-2 / isolation & purification

Grants and funding

Q.-H.L. has received funding from the National Natural Science Foundation of China (http://www.nsfc.gov.cn/, No. 62003230), Chengdu Science and Technology Bureau (http://cdst.chengdu.gov.cn/, No. 2020-YF05-00073-SN), the Fundamental Research Funds for the Central Universities (http://www.moe.gov.cn/, No. 1082204112289), the Science and Technology Department of Sichuan Province (http://kjt.sc.gov.cn/, No. 2020YFS0009), the Special Funds for Prevention and Control of COVID-19 of Sichuan University (http://www.scu.edu.cn/, No. 0082604151026). H.Y. has received funding from the National Science Fund for Distinguished Young Scholars (http://www.nsfc.gov.cn/, No. 81525023) and National Science and Technology Major Project of China (http://www.nsfc.gov.cn/, No. 2018ZX10713001-007, No. 2017ZX10103009-005, No.2018ZX10201001-010). W.Z. has received funding from the Science and Technology Department of Sichuan Province (http://kjt.sc.gov.cn/, No. 2020YFS0007). T.Z. has received funding from the National Natural Science Foundation of China (http://www.nsfc.gov.cn/No.11975071, No. 61673085). The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.