BMJ Open (Sep 2021)

Transmission dynamics and the effects of non-pharmaceutical interventions in the COVID-19 outbreak resurged in Beijing, China: a descriptive and modelling study

  • Ke Ma,
  • Xin Lin,
  • Lin Zhao,
  • Na Jia,
  • Jingyuan Wang,
  • Xiaoming Cui,
  • Yuhao Zhou,
  • Runze Ye,
  • Jia-Fu Jiang,
  • Baogui Jiang,
  • Zhang Xiong,
  • HongHao Shi,
  • Wuchun Cao

DOI
https://doi.org/10.1136/bmjopen-2020-047227
Journal volume & issue
Vol. 11, no. 9

Abstract

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Objective To evaluate epidemiological characteristics and transmission dynamics of COVID-19 outbreak resurged in Beijing and to assess the effects of three non-pharmaceutical interventions.Design Descriptive and modelling study based on surveillance data of COVID-19 in Beijing.Setting Outbreak in Beijing.Participants The database included 335 confirmed cases of COVID-19.Methods To conduct spatiotemporal analyses of the outbreak, we collected individual records on laboratory-confirmed cases of COVID-19 from 11 June 2020 to 5 July 2020 in Beijing, and visitor flow and products transportation data of Xinfadi Wholesale Market. We also built a modified susceptible-exposed-infected-removed model to investigate the effect of interventions deployed in Beijing.Results We found that the staff working in the market (52.2%) and the people around 10 km to this epicentre (72.5%) were most affected, and the population mobility entering-exiting Xinfadi Wholesale Market significantly contributed to the spread of COVID-19 (p=0.021), but goods flow of the market had little impact on the virus spread (p=0.184). The prompt identification of Xinfadi Wholesale Market as the infection source could have avoided a total of 25 708 (95% CI 13 657 to 40 625) cases if unnoticed transmission lasted for a month. Based on the model, we found that active screening on targeted population by nucleic acid testing alone had the most significant effect.Conclusions The non-pharmaceutical interventions deployed in Beijing, including localised lockdown, close-contact tracing and community-based testing, were proved to be effective enough to contain the outbreak. Beijing has achieved an optimal balance between epidemic containment and economic protection.