1. Epidemiology and Global Health
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Evidence for transmission of COVID-19 prior to symptom onset

  1. Lauren C Tindale
  2. Jessica E Stockdale
  3. Michelle Coombe
  4. Emma S Garlock
  5. Wing Yin Venus Lau
  6. Manu Saraswat
  7. Louxin Zhang
  8. Dongxuan Chen
  9. Jacco Wallinga
  10. Caroline Colijn  Is a corresponding author
  1. University of British Columbia, Canada
  2. Simon Fraser University, Canada
  3. National University of Singapore, Singapore
  4. National Institute for Public Health and the Environment, Netherlands
  5. Leiden University Medical Center, Netherlands
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Cite this article as: eLife 2020;9:e57149 doi: 10.7554/eLife.57149

Abstract

We collated contact tracing data from COVID-19 clusters in Singapore and Tianjin, China and estimated the extent of pre-symptomatic transmission by estimating incubation periods and serial intervals. The mean incubation periods accounting for intermediate cases were 4.91 days (95%CI 4.35, 5.69) and 7.54 (95%CI 6.76, 8.56) days for Singapore and Tianjin, respectively. The mean serial interval was 4.17 (95%CI 2.44, 5.89) and 4.31 (95%CI 2.91, 5.72) days (Singapore, Tianjin). The serial intervals are shorter than incubation periods, suggesting that pre-symptomatic transmission may occur in a large proportion of transmission events (0.4-0.5 in Singapore and 0.6-0.8 in Tianjin, in our analysis with intermediate cases, and more without intermediates). Given the evidence for pre-symptomatic transmission it is vital that even individuals who appear healthy abide by public health measures to control COVID-19.

Article and author information

Author details

  1. Lauren C Tindale

    Pathology and Laboratory Medicine, University of British Columbia, Vancouver, Canada
    Competing interests
    No competing interests declared.
  2. Jessica E Stockdale

    Mathematics, Simon Fraser University, Burnaby, Canada
    Competing interests
    No competing interests declared.
  3. Michelle Coombe

    School of Population and Public Health, University of British Columbia, Vancouver, Canada
    Competing interests
    No competing interests declared.
  4. Emma S Garlock

    Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, Canada
    Competing interests
    No competing interests declared.
  5. Wing Yin Venus Lau

    Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, Canada
    Competing interests
    No competing interests declared.
  6. Manu Saraswat

    Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, Canada
    Competing interests
    No competing interests declared.
  7. Louxin Zhang

    Department of Mathematics, National University of Singapore, Singapore, Singapore
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-0260-824X
  8. Dongxuan Chen

    Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, Netherlands
    Competing interests
    No competing interests declared.
  9. Jacco Wallinga

    Faculteit Geneeskunde, Leiden University Medical Center, Leiden, Netherlands
    Competing interests
    Jacco Wallinga, Reviewing editor, eLife.
  10. Caroline Colijn

    Mathematics, Simon Fraser University, Burnaby, Canada
    For correspondence
    ccolijn@sfu.ca
    Competing interests
    Caroline Colijn, Reviewing editor, eLife.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-6097-6708

Funding

Government of Canada (Canada 150 Research Chair program)

  • Caroline Colijn

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Reviewing Editor

  1. Marc Lipsitch, Harvard TH Chan School of Public Health, United States

Publication history

  1. Received: March 23, 2020
  2. Accepted: June 21, 2020
  3. Accepted Manuscript published: June 22, 2020 (version 1)

Copyright

© 2020, Tindale et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

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