Serological prevalence of SARS-CoV-2 infection and associated factors in healthcare workers in a “non-COVID” hospital in Mexico City

  1. Esteban Cruz-Arenas
  2. Elizabeth Cabrera-Ruiz
  3. Sara Laguna-Barcenas
  4. Claudia A. Colin-Castro
  5. Tatiana Chavez
  6. Rafael Franco-Cendejas
  7. Clemente Ibarra
  8. Javier Perez-Orive

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Abstract

Mexico is one of the countries with the highest number of deaths from the COVID-19 pandemic. In spite of this high mortality, in Mexico the number of confirmed cases and diagnostic tests per million population are lower than for other comparable countries, which leads to uncertainty about the actual extent of the pandemic. In Mexico City, healthcare workers represent an important fraction of individuals with SARS-CoV-2 infection. We performed a cross-sectional study whose objective was to estimate the frequency of antibodies to SARS-CoV-2 and identify associated factors in healthcare workers at a large hospital in Mexico City.

Methods

We conducted a serological survey in a non-COVID national referral teaching hospital. The study population included all the personnel that works, in any capacity, in the hospital. From this population we selected a representative sample of 300 individuals. Blood samples were collected and questionnaires were applied between August 10 th and September 9 th , 2020.

Results

ELISA results indicate a serological prevalence of SARS-CoV-2 infection of 13.0%. Working in the janitorial and security groups, having an educational level below a university degree, and living with a larger number of people, were all identified as sociodemographic factors that increase the probability of having SARS-CoV-2 infection.

Conclusions

Less favored socioeconomic groups face significantly higher prospects of experiencing SARS-CoV-2 infection and in institutions such as ours, providing janitorial and security workgroups with additional testing and counseling could help to limit the spread of contagion. The rate from the official number of confirmed cases in Mexico City is substantially smaller than the seropositive rate identified in this work.

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  1. Version published to 10.1371/journal.pone.0255916
  2. Version published to 10.1101/2020.11.30.20241331v2 on medRxiv
  3. ScreenIT

    SciScore for 10.1101/2020.11.30.20241331: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board StatementConsent: Inclusion criteria were: being personnel working in the hospital, from any shift, and granting written informed consent.
    IRB: The study was approved by the hospital’s Ethics and Research Committees (approval number INR-26/20, approval date July 6th, 2020) and was carried out in accordance with relevant guidelines and regulations, including the Declaration of Helsinki.
    RandomizationWe selected participants randomly from each of the 10 work group strata, according to the size of each.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    The LFA tests were the COVID-19 IgG/IGm Rapid Test Cassette® (Hangzhou Biotest Biotech Co. Ltd., China), which use an immunochromatographic assay to provide qualitative detection of IgM and IgG antibodies against the SARS-CoV-2 virus.
    COVID-19 IgG/IGm
    suggested: None
    The ELISA tests we used were the Euroimmun® Anti-SARS-CoV-2 NCP which detect IgG antibodies against the SARS-CoV-2 nucleocapsid protein (Euroimmun Medizinische Labordiagnostika, AG, Germany).
    Anti-SARS-CoV-2 NCP which detect IgG
    suggested: None
    SARS-CoV-2 nucleocapsid protein
    suggested: None
    Software and Algorithms
    SentencesResources
    Statistical analysis: We conducted all statistical analyses with Stata v13.0 (StataCorp, USA).
    StataCorp
    suggested: (Stata, RRID:SCR_012763)

    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: An explicit section about the limitations of the techniques employed in this study was not found. We encourage authors to address study limitations.

    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.
    • No funding statement was detected.
    • 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.

  4. Version published to 10.1101/2020.11.30.20241331v1 on medRxiv