Dating first cases of COVID-19

PLoS Pathog. 2021 Jun 24;17(6):e1009620. doi: 10.1371/journal.ppat.1009620. eCollection 2021 Jun.

Abstract

Questions persist as to the origin of the COVID-19 pandemic. Evidence is building that its origin as a zoonotic spillover occurred prior to the officially accepted timing of early December, 2019. Here we provide novel methods to date the origin of COVID-19 cases. We show that six countries had exceptionally early cases, unlikely to represent part of their main case series. The model suggests a likely timing of the first case of COVID-19 in China as November 17 (95% CI October 4). Origination dates are discussed for the first five countries outside China and each continent. Results infer that SARS-CoV-2 emerged in China in early October to mid-November, and by January, had spread globally. This suggests an earlier and more rapid timeline of spread. Our study provides new approaches for estimating dates of the arrival of infectious diseases based on small samples that can be applied to many epidemiological situations.

Publication types

  • Historical Article
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • COVID-19* / epidemiology
  • COVID-19* / history
  • COVID-19* / transmission
  • China / epidemiology
  • History, 21st Century
  • Humans
  • Pandemics / history*
  • SARS-CoV-2*
  • Zoonoses* / epidemiology
  • Zoonoses* / history
  • Zoonoses* / transmission

Grants and funding

I.J. was funded by The J.E. Purkyně Fellowship of the Czech Academy of Sciences. DLR and JSR received no specific funding for this work. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.