SARS-CoV-2 Seroprevalence Among All Workers in a Teaching Hospital in Spain: Unmasking The Risk

  1. M Isabel Galán
  2. María Velasco
  3. M Luisa Casas
  4. M José Goyanes
  5. Gil Rodríguez-Caravaca
  6. Juan Emilio Losa
  7. Carmen Noguera
  8. Virgilio Castilla
  9. Working Group Alcorcon COVID-19 investigators

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Abstract

Background

Health-care workers (HCW) are at increased risk for SARS-CoV-2 infection, but few studies have evaluated prevalence of antibodies against SARS-CoV-2 among them.

Objective

To determine the seroprevalence against SARS-CoV-2 in all HCW.

Methods

Cross-sectional study (April 14 th - 27 th , 2020) of all HCW at Hospital Universitario Fundación Alcorcón, a second level teaching hospital in Madrid, Spain. SARS-CoV-2 IgG was measured by ELISA. HCW were classified by professional category, working area, and risk for SARS-CoV-2 exposure.

Results

Among 2919 HCW, 2590 (90.5%) were evaluated. Mean age was 43.8 years (SD 11.1) and 73.9% were females. Globally, 818 (31.6%) workers were IgG positive, with no differences for age, sex or previous diseases. Among them, 48.5% did not report previous symptoms. Seropositivity was more frequent in high (33.1%) and medium (33.8%) than in low-risk areas (25.8%, p = 0.007), but no difference was found for hospitalization areas attending COVID-19 and non-COVID-19 patients (35.5 vs 38.3% p = NS). HCW with a previous SARS-CoV2 PCR positive test were IgG seropositive in 90.8%. By multivariate logistic regression analysis, seropositivity was associated with being physicians (OR 2.37, CI95% 1.61–3.49), nurses (OR 1.67, CI95% 1.14–2.46), or nurse- assistants (OR 1.84, CI95% 1.24–2.73), HCW working at COVID-19 hospitalization areas (OR 1.71, CI95% 1.22–2.40), non-COVID-19 hospitalization areas (OR 1.88, CI95% 1.30–2.73), and at the Emergency Room (OR 1.51, CI95% 1.01–2.27)

Conclusions

Seroprevalence uncovered a high rate of infection previously unnoticed among HCW. Patients not suspected of having COVID-19 as well as asymptomatic HCW may be a relevant source for nosocomial SARS-CoV-2 transmission.

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  1. ScreenIT

    SciScore for 10.1101/2020.05.29.20116731: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board StatementConsent: Statistical analysis was performed, with hypothesis testing based on a two-tailed test of significance and we considered statistical significance P< 0.05 with the Statistical Package for Social Sciences (SPSSPC v 20 Illinois USA) Study approval / Ethics: All participants enrolled into the study voluntarily, and written informed consent was required to use the data for analysis.
    IRB: The study protocol was approved by the HUFA independent ethics research committee (reference number 20/69).
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    No key resources detected.

    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 some limitations that deserve consideration. First, we do not have data about Ig M or concurrent PCR. However, our study was designed to have a picture of past exposure to the virus in all our workers. We did not pursue an evolutionary perspective of the disease. Second, the samples were collected over two weeks, so the interpretation of the prevalence must be related to the average prevalence at that time. Nonetheless, our work has several strengths. First, the quality of the technology we had used seems to be one of the highest sensitivities available (ELISA)47–49. Second, we had a virtually universal representation of all workers of the hospital (90%), including external employees, an evaluation hardly performed. Additionally, we identified the particular function of all employees in a time of changing roles for clinicians in the middle of the crisis. In addition, its close temporal vicinity with the serologic study in the Spanish population allows for a direct comparison. In conclusion, seroprevalence unmasked a high rate of infection previously unnoticed in HCW. Clinical care of COVID-19 unscreened patients is associated with a similar prevalence of SARS-CoV-2 antibodies as the one found in COVID-19 facilities uncovering a relevant source for nosocomial SARS-CoV-2 transmission. In addition, apparently healthy HCW may also be another relevant source for SARS-CoV-2 transmission. HCW testing could reduce in-hospital transmission50. Serosurveys in hospitals may...

    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 10.1101/2020.05.29.20116731 on medRxiv