Longitudinal SARS-CoV-2 serosurveillance of over ten thousand health care workers in the Providence Oregon cohort

  1. Rom Leidner
  2. Angi Frary
  3. Julie Cramer
  4. David Ball
  5. Roshanthi Weerasinghe
  6. Mark Schmidt
  7. Justin Jin
  8. Veronica Luzzi
  9. Alec Saitman
  10. Jeffrey A. Young
  11. David Leidner
  12. Kendall Sawa
  13. Scott Marsal
  14. Kevin Olson
  15. Nancy Frisco
  16. Amy Compton-Phillips
  17. Walter Urba
  18. Brian Piening
  19. Carlo Bifulco

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Abstract

Frontline healthcare workers (HCW) are a high-risk population for SARS-CoV-2 infection. Here we present results from a large serosurveillance study of 10,019 asymptomatic HCW conducted during April-May 2020, in eight hospital medical centers across the state of Oregon, USA during the initial peak of the pandemic. Free and voluntary testing was performed at 14 +/− 3 day intervals, over a 4-week window at each site, utilizing a lab-developed ELISA based on the Epitope Diagnostics COVID-19 nucleocapsid IgG detection Kit. We identified 253 SARS-CoV-2 IgG seropositive individuals among 10,019 total participants, representing a cross-sectional seroprevalence of 2.53%. Subgroup analysis identified differential seropositivity by job role, ranging from 8.03% among housekeepers, odds ratio 3.17 (95% CI 1.59–5.71), to 0.00% among anesthesiologists, odds ratio 0.00 (95% CI 0–0.26), both of which were significant. Over the course of the study, 17 seroconversions (0.25%) and 101 seroreversions (1.50%) were identified. Self-reported SARS-CoV-2 swab qPCR testing, when compared with subsequent serology on study, showed only modest agreement, κ = 0.47 (95% CI 0.32–0.62). Overall, these findings demonstrate relatively low seroprevalence and very low seroconversion rates among HCW in Oregon, USA, over a period in which aggressive social distancing measures were in place. The high rate of seroreversion observed in this cohort, and the relatively high discordance between SARS-CoV-2 serology and swab qPCR, highlight limitations of current detection methods, and stress the need for development of novel assessment methodologies to more accurately identify exposure (and/or immunity) to SARS-CoV-2 in this population.

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  1. ScreenIT

    SciScore for 10.1101/2020.08.16.20176107: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    Institutional Review Board Statementnot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    SARS-CoV-2 nucleocapsid IgG antibody serosurveillance was offered to asymptomatic HCW at 8 Oregon USA Providence medical centers, (Fig. 1).
    SARS-CoV-2 nucleocapsid IgG
    suggested: None
    A horseradish peroxidase (HRP) labeled polyclonal goat anti-human IgG tracer antibody was added to each well.
    anti-human IgG
    suggested: None
    After an incubation period, an immunocomplex of SARS-CoV-2 recombinant antigen – human anti-SARS-CoV-2 IgG antibody – HRP labeled antihuman IgG tracer antibody is formed if there is specific coronavirus IgG antibody present in the tested specimen.
    antihuman IgG
    suggested: (GeneTex Cat# GTX28798, RRID:AB_374523)
    The enzymatic activity of the tracer antibody bound to the anti-SARS-CoV-2 IgG on the wall of the microtiter well is proportional to the amount of the anti-SARS-CoV-2 IgG antibody level in the tested specimen.
    anti-SARS-CoV-2 IgG
    suggested: None

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    The high seroreversion rate and the relatively high discordances between SARS-CoV2 serology and swab qPCR assessment (κ = 0.47; 95% CI 0.32–0.62), also highlight limitations of current detection methods and stress the need for development of novel assessment methodologies. Use of residual sera is permitted in the study for further immunologic analyses, such as orthogonal serologic assay methods. It remains unclear whether the humoral antibody response is fully protective, or whether cellular immunity may be playing a larger role in the clearance of SARS-CoV-213,25,26. In the event of future SARS-CoV-2 seasonal cycling, this protocol allows for reactivation without formal re-review in order to enable timely data capture on re-emergent pandemic/endemic conditions.

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    About SciScore

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  2. Version published to 10.1101/2020.08.16.20176107v1 on medRxiv