Effective control of SARS-CoV-2 transmission in Wanzhou, China

Nat Med. 2021 Jan;27(1):86-93. doi: 10.1038/s41591-020-01178-5. Epub 2020 Nov 30.

Abstract

The effectiveness of control measures to contain coronavirus disease 2019 (COVID-19) in Wanzhou, China was assessed. Epidemiological data were analyzed for 183 confirmed COVID-19 cases and their close contacts from five generations of transmission of severe acute respiratory syndrome coronavirus 2 throughout the entire COVID-19 outbreak in Wanzhou. Approximately 67.2% and 32.8% of cases were symptomatic and asymptomatic, respectively. Asymptomatic and presymptomatic transmission accounted for 75.9% of the total recorded transmission. The reproductive number was 1.64 (95% confidence interval: 1.16-2.40) for G1-to-G2 transmission, decreasing to 0.31-0.39 in later generations, concomitant with implementation of rigorous control measures. Substantially higher infection risk was associated with contact within 5 d after the infectors had been infected, frequent contact and ≥8 h of contact duration. The spread of COVID-19 was effectively controlled in Wanzhou by breaking the transmission chain through social distancing, extensive contact tracing, mass testing and strict quarantine of close contacts.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Basic Reproduction Number
  • COVID-19 / epidemiology*
  • COVID-19 / prevention & control*
  • COVID-19 / transmission
  • Carrier State
  • Child
  • China / epidemiology
  • Communicable Disease Control*
  • Contact Tracing
  • Female
  • Humans
  • Male
  • Middle Aged
  • SARS-CoV-2 / physiology