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Screening of healthcare workers for SARS-CoV-2 highlights the role of asymptomatic carriage in COVID-19 transmission

Research Article
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Cite this article as: eLife 2020;9:e58728 doi: 10.7554/eLife.58728

Abstract

Significant differences exist in the availability of healthcare worker (HCW) SARS-CoV-2 testing between countries, and existing programmes focus on screening symptomatic rather than asymptomatic staff. Over a 3-week period (April 2020), 1,032 asymptomatic HCWs were screened for SARS-CoV-2 in a large UK teaching hospital. Symptomatic staff and symptomatic household contacts were additionally tested. Real-time RT-PCR was used to detect viral RNA from a throat+nose self-swab. 3% of HCWs in the asymptomatic screening group tested positive for SARS-CoV-2. 17/30 (57%) were truly asymptomatic/pauci-symptomatic. 12/30 (40%) had experienced symptoms compatible with coronavirus disease 2019 (COVID-19) >7 days prior to testing, most self-isolating, returning well. Clusters of HCW infection were discovered on two independent wards. Viral genome sequencing showed that the majority of HCWs had the dominant lineage B∙1. Our data demonstrates the utility of comprehensive screening of HCWs with minimal or no symptoms. This approach will be critical for protecting patients and hospital staff.

Article and author information

Author details

  1. Lucy Rivett

    Department of Infectious Diseases, Cambridge University Hospitals NHS Trust, Cambridge, United Kingdom
    Competing interests
    No competing interests declared.
  2. Sushmita Sridhar

    Cambridge Institute for Therapeutic Immunology and Infectious Disease, University of Cambridge, Cambridge, United Kingdom
    Competing interests
    No competing interests declared.
  3. Dominic Sparkes

    Department of Infectious Diseases, Cambridge University Hospitals NHS Trust, Cambridge, United Kingdom
    Competing interests
    No competing interests declared.
  4. Matthew Routledge

    Department of Infectious Diseases, Cambridge University Hospitals NHS Trust, Cambridge, United Kingdom
    Competing interests
    No competing interests declared.
  5. Nick K Jones

    Department of Infectious Diseases, Cambridge University Hospitals NHS Trust, Cambridge, United Kingdom
    Competing interests
    No competing interests declared.
  6. Sally Forrest

    Cambridge Institute for Therapeutic Immunology and Infectious Disease, University of Cambridge, Cambridge, United Kingdom
    Competing interests
    No competing interests declared.
  7. Jamie Young

    Academic Department of Medical Genetics, University of Cambridge, Cambridge, United Kingdom
    Competing interests
    No competing interests declared.
  8. Joana Pereira-Dias

    Cambridge Institute for Therapeutic Immunology and Infectious Disease, University of Cambridge, Cambridge, United Kingdom
    Competing interests
    No competing interests declared.
  9. William L Hamilton

    Department of Infectious Diseases, Cambridge University Hospitals NHS Trust, Cambridge, United Kingdom
    Competing interests
    No competing interests declared.
  10. Mark Ferris

    Department of Occupational Health and Wellbeing, Cambridge University Hospitals NHS Trust, Cambridge, United Kingdom
    Competing interests
    No competing interests declared.
  11. M Estee Torok

    Department of Medicine, University of Cambridge, Cambridge, United Kingdom
    Competing interests
    M Estee Torok, Reports grants from Academy of Medical Sciences and the Health Foundation, non-financial support from National Institute of Health Research, grants from Medical Research Council, grants from Global Challenges Research Fund, personal fees from Wellcome Sanger Institute, personal fees from University of Cambridge, personal fees from Oxford University Press.
  12. Luke Meredith

    Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
    Competing interests
    No competing interests declared.
  13. The CITIID-NIHR COVID-19 BioResource Collaboration

    Cambridge Institute for Therapeutic Immunology and Infectious Disease, University of Cambridge, Cambridge, United Kingdom
    Competing interests
    No competing interests declared.
  14. Martin D Curran

    Clinical Microbiology & Public Health Laboratory, Public Health England (PHE), Cambridge, United Kingdom
    Competing interests
    No competing interests declared.
  15. Stewart Fuller

    Clinical Research Facility, National Institutes for Health Research, Cambridge, United Kingdom
    Competing interests
    No competing interests declared.
  16. Afzal Chaudhry

    Chief Medical Information Officer, Cambridge University Hospitals NHS Trust, Cambridge, United Kingdom
    Competing interests
    Afzal Chaudhry, Reports grants from Cambridge Biomedical Research Centre at CUHNFT.
  17. Ashley Shaw

    Medical Director, Cambridge University Hospitals NHS Trust, Cambridge, United Kingdom
    Competing interests
    No competing interests declared.
  18. Richard J Samworth

    Statistical Laboratory, Centre for Mathematical Sciences, University of Cambridge, Cambridge, United Kingdom
    Competing interests
    Richard J Samworth, Reports grants from EPSRC fellowship.
  19. John R Bradley

    Department of Medicine, University of Cambridge, Cambridge, United Kingdom
    Competing interests
    No competing interests declared.
  20. Gordon Dougan

    Department of Medicine, University of Cambridge, Cambridge, United Kingdom
    Competing interests
    Gordon Dougan, Reports grants from NIHR.
  21. Kenneth G C Smith

    Department of Medicine, University of Cambridge, Cambridge, United Kingdom
    Competing interests
    Kenneth G C Smith, Reports grants from Wellcome Trust.
  22. Paul J Lehner

    Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
    Competing interests
    Paul J Lehner, Reports grants from Wellcome Trust and Addenbrooke's Charitable Trust.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-9383-1054
  23. Nicholas J Matheson

    Department of Medicine, University of Cambridge, Cambridge, United Kingdom
    Competing interests
    Nicholas J Matheson, Reports grants from MRC (UK) and NHS Blood and Transfusion.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-3318-1851
  24. Giles Wright

    Department of Occupational Health and Wellbeing, Cambridge University Hospitals NHS Trust, Cambridge, United Kingdom
    Competing interests
    No competing interests declared.
  25. Ian G Goodfellow

    Department of Pathology, University of Cambridge, Cambridge, United Kingdom
    Competing interests
    Ian G Goodfellow, Reports grants from Wellcome Trust and Addenbrooke's Charitable Trust.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-9483-510X
  26. Stephen Baker

    Department of Medicine, University of Cambridge, Cambridge, United Kingdom
    Competing interests
    Stephen Baker, Reports grants from Wellcome Trust and Addenbrooke's Charitable Trust.
  27. Michael P Weekes

    Cambridge Institute for Therapeutic Immunology and Infectious Disease, University of Cambridge, Cambridge, United Kingdom
    For correspondence
    mpw1001@cam.ac.uk
    Competing interests
    Michael P Weekes, Reports grants from Wellcome Trust.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-3196-5545

Funding

Wellcome (108070/Z/15/Z)

  • Michael P Weekes

Addenbrooke's Charitable Trust, Cambridge University Hospitals

  • Paul J Lehner

Medical Research Council (MR/P008801/1)

  • Nicholas J Matheson

NHS Blood and Transplant (WPA15-02)

  • Nicholas J Matheson

National Institute for Health Research (Cambridge Biomedical Research Centre)

  • John R Bradley

National Institute for Health Research (Cambridge Biomedical Research Centre)

  • M Estee Torok

National Institute for Health Research (Cambridge Biomedical Research Centre)

  • Afzal Chaudhry

National Institute for Health Research (Cambridge Biomedical Research Centre)

  • Gordon Dougan

Academy of Medical Sciences (Clinician Scientist Fellowship)

  • M Estee Torok

Engineering and Physical Sciences Research Council (EP/P031447/1)

  • Richard J Samworth

Engineering and Physical Sciences Research Council (EP/N031938/1)

  • Richard J Samworth

Wellcome (215515/Z/19/Z)

  • Stephen Baker

Cancer Research UK (PRECISION Grand Challenge C38317/A24043)

  • Jamie Young

Wellcome (207498?Z/17/Z)

  • Ian G Goodfellow

Wellcome (206298/B/17/Z)

  • Ian G Goodfellow

Wellcome (210688/Z/18/Z)

  • Paul J Lehner

Wellcome (200871/Z/16/Z)

  • Kenneth G C Smith

Addenbrooke's Charitable Trust, Cambridge University Hospitals

  • Michael P Weekes

Addenbrooke's Charitable Trust, Cambridge University Hospitals

  • Stephen Baker

Addenbrooke's Charitable Trust, Cambridge University Hospitals

  • Ian G Goodfellow

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

Ethics

Human subjects: As a study of healthcare-associated infections, this investigation is exempt from requiring ethical approval under Section 251 of the NHS Act 2006 (see also the NHS Health Research Authority algorithm, available at http://www.hra-decisiontools.org.uk/research/, which concludes that no formal ethical approval is required). Written consent was obtained from each HCW described in the anonymised case vignettes.

Reviewing Editor

  1. Jos WM van der Meer, Radboud University Medical Centre, Netherlands

Publication history

  1. Received: May 8, 2020
  2. Accepted: May 10, 2020
  3. Accepted Manuscript published: May 11, 2020 (version 1)

Copyright

© 2020, Rivett 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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