Seroprevalence of SARS-CoV-2 IgG specific antibodies among healthcare workers in the Northern Metropolitan Area of Barcelona, Spain, after the first pandemic wave

  1. Jaume Barallat
  2. Gema Fernández-Rivas
  3. Bibiana Quirant-Sánchez
  4. Victoria González
  5. Maria Doladé
  6. Eva Martinez-Caceres
  7. Monica Piña
  8. Joan Matllo
  9. Oriol Estrada
  10. Ignacio Blanco

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Abstract

The rapid spread of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) around the world has caused a global pandemic, infecting millions of individuals, with an unprecedented impact in health care systems worldwide. Healthcare workers are one of the risk groups that need to be well protected, due to their strategic role in patient management, presently and in prevention of healthcare needs for future outbreaks. Here, we present the results of the first SARS-CoV-2 seroprevalence study in the Northern Metropolitan Area of Barcelona, Spain.

Methods

IgG SARS-CoV-2 antibodies were analyzed in serum samples from 7563 healthcare workers of the Northern Metropolitan Area of Barcelona. Samples were collected after the first pandemic wave (from May 4th to May 22nd, 2020) and were analyzed by automated chemiluminescence assays. All samples were tested for IgG anti-S1/S2. Participant samples with negative or equivocal results but with analytical signals above the limit of detection and/or previously confirmed COVID-19 diagnosis were also tested for IgG anti-Nucleocapsid.

Results

A total of 779 of 7563 (10.3%) healthcare workers were positive for anti-SARS-CoV-2 IgG (specific for either S1/S2 or N antigens). No significant differences were observed between those working at primary care or at the reference hospital. Interestingly, among 341 participants with a confirmed COVID-19 diagnosis, 36 (10.55%) tested negative for SARS-CoV-2 IgG (both S1/S2 and recombinant N antigen).

Conclusion

Seroprevalence of anti-SARS-CoV-2 IgG in the healthcare workers of the North Metropolitan Area of Barcelona was higher than in the general population in the same geographical area. Safety measures have to be stressed in order to protect these essential workers from future pandemic waves.

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  1. Version published to 10.1371/journal.pone.0244348
  2. ScreenIT

    SciScore for 10.1101/2020.06.24.20135673: (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
    From May 4th to May 22nd, 2020, all Healthcare workers of the ICS-Northern Metropolitan Area of Barcelona (n=9315) were offered to have serum testing performed for SARS-CoV-2 IgG antibodies.
    SARS-CoV-2 IgG
    suggested: None
    Software and Algorithms
    SentencesResources
    In this case, a SARS-CoV-2 IgG test (Abbott Diagnostics, Sligo, Ireland) was run on an Architect i2000 platform. (Figure 1).
    Abbott
    suggested: (Abbott, RRID:SCR_010477)
    These analyses were conducted with version 20 of SPSS.
    SPSS
    suggested: (SPSS, RRID:SCR_002865)

    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:
    Our study has several limitations. No other immunoglobulin isotypes were analyzed, and it cannot be discarded that some individuals might be positive for IgA or IgM and the moment of blood extraction. Moreover, not all antigens have been tested in all individuals. Only those with a report of disease or with detectable but non-positive SARS-CoV-2 IgG S1/2 were analyzed for both N and S antigens. Nevertheless, some strong points can be considered in the current study. First, the large number of individuals tested in a clearly restricted sanitary area suffering a high impact of the pandemic. Second, the study set-up, in the context of a high throughput diagnostic laboratory, showing the technical viability of testing high number of patients in a short period. Third, the concordance of the results with reported infection and/or rRT-PCR results from the staff. Interestingly, this study opens new research perspectives, as it has identified a group of individuals in which, despite of having suffered COVID19 infection, not detectable antibodies were found. Further analysis considering broader antibodies isotypes as well as cellular responses need to be implemented in routine bases to better characterize these population. In summary, we report that seroprevalence of anti-SARS-CoV-2 IgG antibodies in the healthcare workers of the Nord Metropolitan Area of Barcelona gives was slightly increased in comparison with the general population in the same geographical area and similar to other ...

    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.
    • Thank you for including a protocol registration statement.

    About SciScore

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  3. Version published to 10.1101/2020.06.24.20135673v1 on medRxiv