Seroprevalence of antibodies against SARS-CoV-2 among health care workers in a large Spanish reference hospital

  1. Alberto L. Garcia-Basteiro
  2. Gemma Moncunill
  3. Marta Tortajada
  4. Marta Vidal
  5. Caterina Guinovart
  6. Alfons Jiménez
  7. Rebeca Santano
  8. Sergi Sanz
  9. Susana Méndez
  10. Anna Llupià
  11. Ruth Aguilar
  12. Selena Alonso
  13. Diana Barrios
  14. Carlo Carolis
  15. Pau Cisteró
  16. Eugenia Chóliz
  17. Angeline Cruz
  18. Silvia Fochs
  19. Chenjerai Jairoce
  20. Jochen Hecht
  21. Montserrat Lamoglia
  22. Mikel J. Martínez
  23. Robert A. Mitchell
  24. Natalia Ortega
  25. Nuria Pey
  26. Laura Puyol
  27. Marta Ribes
  28. Neus Rosell
  29. Patricia Sotomayor
  30. Sara Torres
  31. Sarah Williams
  32. Sonia Barroso
  33. Anna Vilella
  34. José Muñoz
  35. Antoni Trilla
  36. Pilar Varela
  37. Alfredo Mayor
  38. Carlota Dobaño

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Abstract

Health care workers (HCW) are a high-risk population to acquire SARS-CoV-2 infection from patients or other fellow HCW. This study aims at estimating the seroprevalence against SARS-CoV-2 in a random sample of HCW from a large hospital in Spain. Of the 578 participants recruited from 28 March to 9 April 2020, 54 (9.3%, 95% CI: 7.1–12.0) were seropositive for IgM and/or IgG and/or IgA against SARS-CoV-2. The cumulative prevalence of SARS-CoV-2 infection (presence of antibodies or past or current positive rRT-PCR) was 11.2% (65/578, 95% CI: 8.8–14.1). Among those with evidence of past or current infection, 40.0% (26/65) had not been previously diagnosed with COVID-19. Here we report a relatively low seroprevalence of antibodies among HCW at the peak of the COVID-19 epidemic in Spain. A large proportion of HCW with past or present infection had not been previously diagnosed with COVID-19, which calls for active periodic rRT-PCR testing in hospital settings.

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  1. Version published to 10.1038/s41467-020-17318-x
  2. ScreenIT

    SciScore for 10.1101/2020.04.27.20082289: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board StatementConsent: After obtaining written informed consent, we filled out a standardized electronic questionnaire programmed in REDCap (Research Electronic Data Capture)14 for each participant, with the following information: demographics (age, sex, household size, etc.), professional information (occupation, hospital department, shift), clinical information such as history of COVID-19-compatible symptoms during the previous month (cough, sore throat,
    IACUC: Laboratory procedures: Ethical considerations: The protocol and informed consent form were reviewed and approved by the Institutional Review Board (IRB) at HCB (CEIm) prior to study implementation (Ref number: HCB/2020/0336).
    IRB: Laboratory procedures: Ethical considerations: The protocol and informed consent form were reviewed and approved by the Institutional Review Board (IRB) at HCB (CEIm) prior to study implementation (Ref number: HCB/2020/0336).
    RandomizationStudy design, population and setting: The study design consists of a series of four cross-sectional surveys (at baseline, 1 month, 6 months and 12 months) in a cohort of randomly selected HCW from Hospital Clínic of Barcelona (HCB).
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    After obtaining written informed consent, we filled out a standardized electronic questionnaire programmed in REDCap (Research Electronic Data Capture)14 for each participant, with the following information: demographics (age, sex, household size, etc.), professional information (occupation, hospital department, shift), clinical information such as history of COVID-19-compatible symptoms during the previous month (cough, sore throat,
    REDCap
    suggested: (REDCap, RRID:SCR_003445)

    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:
    This study has several limitations. First, we collected data over a 12-day period, which, in the context of a rapidly growing epidemic, hinders its association to a specific date, with the prevalence having to be interpreted as the average prevalence over those 12 days. Second, we only collected nasopharyngeal samples (instead of oropharyngeal and nasopharyngeal) from study participants for the molecular detection of SARS-CoV-2 RNA. Although this could reduce rRT-PCR sensitivity, there is evidence showing that nasopharyngeal samples have a higher positivity rate than oropharyngeal samples.36 Third, the invalid rRT-PCR results obtained from 43 (7.4%) of the nasopharyngeal swabs analyzed might have led to an under-estimation of overall prevalence of exposure to the virus. Fourth, seroprevalence was defined as positivity of any of the antibody isotypes (IgM, IgG, IgA), which maximized sensitivity rather than specificity. However, our Luminex assay validation showed excellent specificity for the three isotypes, thus, our potential overestimation of the true prevalence is likely to be minimized. Finally, our participation rate (74%) could have introduced selection bias in our sample. It could be that many of those refusing to participate might have had a characteristic associated to an increased risk of infection (being very busy at COVID-19 units, for example). Thus, the impact is potentially minimal, given the lack of association of this and most studied variables with our prima...

    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

    SciScore is an automated tool that is designed to assist expert reviewers by finding and presenting formulaic information scattered throughout a paper in a standard, easy to digest format. SciScore checks for the presence and correctness of RRIDs (research resource identifiers), and for rigor criteria such as sex and investigator blinding. For details on the theoretical underpinning of rigor criteria and the tools shown here, including references cited, please follow this link.

  3. Version published to 10.1101/2020.04.27.20082289v1 on medRxiv