Seroprevalence of the SARS-CoV-2 infection in health workers of the Sanitary Region VIII, at province of Buenos Aires

  1. Andrea P. Silva
  2. M. Fernanda Aguirre
  3. Christian Ballejo
  4. M. Jimena Marro
  5. Andrea V. Gamarnik
  6. Gastón Vargas
  7. Marina Pifano
  8. Teresa B. Varela
  9. Enio García
  10. Alicia EB Lawrynowicz
  11. Osvaldo C. Uez
  12. Irene Pagano

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Abstract

Introduction

The aim of this study was to estimate the seroprevalence of the SARS-CoV-2 infection in health workers of the Sanitary Region VIII, at province of Buenos Aires during June 2020.

Methods

A cross-sectional design was used. A probabilistic sampling by two-stage conglomerates was carried out. Data were collected from a self-administered questionnaire and a blood sample for antibody identification. The COVIDAR IgG and IgM test were used. RESULTS: 738 health workers were included; the overall response rate was 73.80%. 71.83% of that were women; age showed a normal distribution. Nurses and doctors accounted for more than half of the staff. 75.86% of people claimed to always use Personal Protective Equipment. 5.61% of people had close contact with a confirmed case of COVID-19. 4.60% of people had previously had a nasopharyngeal swab with a negative result. Five workers had positive IgG for SARS-CoV-2 (four women and one man) with negative IgM. The mean age of the cases was 35 years old; two of them were asymptomatic; neither of them had a swab sample taken. The overall seroprevalence was 0.75%, with no significant differences between strata.

Discussion

The seroprevalence found was low; indicating a large proportion of workers was susceptible to infection. We stress the need to complement passive epidemiological surveillance strategies with serological monitoring in health workers.

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  1. ScreenIT

    SciScore for 10.1101/2020.09.07.20189050: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board StatementConsent: All workers who signed an informed consent were included.
    IRB: The investigation initiative was approved by the INE Research Ethics Committee registered under code CE00264 in the National Registry of Health Research (RENIS, by its acronym in Spanish) authorized by the Central Ethics Committee no. 059/2019
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    It consists of an immuno-enzymatic non-competitive heterogeneous assay based on an indirect in-vitro detection method for specific IgG antibodies for the SARS-CoV-2 spike protein in human serum or plasma samples20.
    specific IgG
    suggested: None
    In case isotype IgG antibodies were detected, IgM would be determined using the COVIDAR IgM test (ANMAT PM
    In case isotype 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:
    This study has strengths and weaknesses. Regarding its strengths, we can highlight the random sampling strategy which allowed to get a direct measure of the infection dimension on one of the most vulnerable population groups during the pandemic. There was a high overall response rate which clearly shows the commitment of the individuals involved and also contributed to obtain reliable estimations. As of May 1 of this year, methodological biases were found in a systematic review of the SARS-CoV-2 seroprevalence results, mostly due to omission of random sampling in their target population. On the other hand, at this moment, which is almost synchronous with the preparation stage of this investigation field, only 14 countries in the world had reported seroprevalence results as part of completed or ongoing studies25. Regarding the weaknesses, the small amount of cases found did not allow to carry out an infection risk analysis according to different characteristics of the health care workers such as occupation or comorbidity history. The fieldwork done in order to obtain the required data for the sampling frame implied a great effort on the part of the research team since the information available was not integrated in only one database and had to be developed. In this regard, we highlight the need to improve the health care information systems in Argentina to allow for the possibility to access appropriate records.

    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 10.1101/2020.09.07.20189050 on medRxiv