High infectiousness immediately before COVID-19 symptom onset highlights the importance of continued contact tracing

  1. William Stephen Hart  Is a corresponding author
  2. Philip K Maini
  3. Robin N Thompson
  1. University of Oxford, United Kingdom
  2. University of Warwick, United Kingdom

Abstract

Background: Understanding changes in infectiousness during SARS-COV-2 infections is critical to assess the effectiveness of public health measures such as contact tracing.

Methods: Here, we develop a novel mechanistic approach to infer the infectiousness profile of SARS-COV-2 infected individuals using data from known infector-infectee pairs. We compare estimates of key epidemiological quantities generated using our mechanistic method with analogous estimates generated using previous approaches.

Results: The mechanistic method provides an improved fit to data from SARS-CoV-2 infector-infectee pairs compared to commonly used approaches. Our best-fitting model indicates a high proportion of presymptomatic transmissions, with many transmissions occurring shortly before the infector develops symptoms.

Conclusions: High infectiousness immediately prior to symptom onset highlights the importance of continued contact tracing until effective vaccines have been distributed widely, even if contacts from a short time window before symptom onset alone are traced.

Funding: Engineering and Physical Sciences Research Council (EPSRC).

Data availability

All data generated or analysed during this study are included in the manuscript and supporting files. A source data file has been provided for Figure 2, containing the SARS-CoV-2 transmission pair data used in our analyses. These data were originally reported in references (3,10,29-31), and the combined data were also considered in reference (4). Code for reproducing our results is available at https://github.com/will-s-hart/COVID-19-Infectiousness-Profile.

Article and author information

Author details

  1. William Stephen Hart

    Mathematical Institute, University of Oxford, Oxford, United Kingdom
    For correspondence
    william.hart@keble.ox.ac.uk
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-2504-6860
  2. Philip K Maini

    Mathematical Institute, University of Oxford, Oxford, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  3. Robin N Thompson

    Mathematics Institute, University of Warwick, Coventry, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.

Funding

Engineering and Physical Sciences Research Council (Excellence Award)

  • William Stephen Hart

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

Copyright

© 2021, Hart 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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  1. William Stephen Hart
  2. Philip K Maini
  3. Robin N Thompson
(2021)
High infectiousness immediately before COVID-19 symptom onset highlights the importance of continued contact tracing
eLife 10:e65534.
https://doi.org/10.7554/eLife.65534

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https://doi.org/10.7554/eLife.65534

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