SARS-CoV-2 seroprevalence among healthcare workers

Talia D. Wiggen, Bruno Bohn, Angela K. Ulrich, Steven D. Stovitz, Ali J. Strickland, Brianna M. Naumchik, Sara Walsh, Stephen Smith, Brett Baumgartner, Susan Kline, Stephanie Yendell, Craig Hedberg, Timothy J. Beebe, Ryan T. Demmer

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Background Monitoring COVID-19 infection risk among health care workers (HCWs) is a public health priority. We examined the seroprevalence of SARS-CoV-2 among HCWs following the fall infection surge in Minnesota, and before and after COVID-19 vaccination. Additionally, we assessed demographic and occupational risk factors for SARS-CoV-2 infection. Methods We conducted two rounds of seroprevalence testing among a cohort of HCWs: samples in round 1 were collected from 11/22/20–02/21/21 and in round 2 from 12/18/20–02/15/21. Demographic and occupational exposures assessed with logistic regression were age, sex, healthcare role and setting, and number of children in the household. The primary outcome was SARS-CoV-2 IgG seropositivity. A secondary outcome, SARS-CoV-2 infection, included both seropositivity and self-reported SARS-CoV-2 test positivity. Results In total, 459 HCWs were tested. 43/454 (9.47%) had a seropositive sample 1 and 75/423 (17.7%) had a seropositive sample 2. By time of sample 2 collection, 54% of participants had received at least one vaccine dose and seroprevalence was 13% among unvaccinated individuals. Relative to physicians, the odds of SARS-CoV-2 infection in other roles were increased (Nurse Practitioner: OR[95%CI] 1.93[0.57,6.53], Physician’s Assistant: 1.69 [0.38,7.52], Nurse: 2.33[0.94,5.78], Paramedic/EMTs: 3.86[0.78,19.0], other: 1.68 [0.58,4.85]). The workplace setting was associated with SARS-CoV-2 infection (p = 0.04). SARS-CoV-2 seroprevalence among HCWs reporting duties in the ICU vs. those working in an ambulatory clinic was elevated: OR[95%CI] 2.17[1.01,4.68]. Conclusions SARS-CoV-2 seroprevalence in HCW increased during our study period which was consistent with community infection rates. HCW role and setting—particularly working in the ICU —is associated with higher risk for SARS-CoV-2 infection.

Original languageEnglish (US)
Article numbere0266410
JournalPloS one
Issue number4 April
StatePublished - Apr 2022

Bibliographical note

Funding Information:
This study was supported by funding from the Minnesota Department of Health Contract Number 183558. Funding to establish the cohort was provided by The University of Minnesota Office of the Vice President for Research, the Minnesota Population Center (funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development Population Research Infrastructure Program P2C HD041023), and by The University of Minnesota?s NIH Clinical and Translational Science Award: UL1TR002494. Dr. Ulrich was supported by NIH grant T32AI05543315. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Publisher Copyright:
Copyright: © 2022 Wiggen et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


  • COVID-19/epidemiology
  • COVID-19 Vaccines
  • Child
  • Health Personnel
  • Humans
  • SARS-CoV-2
  • Seroepidemiologic Studies

PubMed: MeSH publication types

  • Research Support, Non-U.S. Gov't
  • Journal Article
  • Research Support, N.I.H., Extramural


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