PLoS ONE (Jan 2022)

A prospective study of asymptomatic SARS-CoV-2 infection among individuals involved in academic research under limited operations during the COVID-19 pandemic

  • Audrey Pettifor,
  • Bethany L. DiPrete,
  • Bonnie E. Shook-Sa,
  • Lakshmanane Premkumar,
  • Kriste Kuczynski,
  • Dirk Dittmer,
  • Allison Aiello,
  • Shannon Wallet,
  • Robert Maile,
  • Joyce Tan,
  • Ramesh Jadi,
  • Linda Pluta,
  • Aravinda M. de Silva,
  • David J. Weber,
  • Min Kim,
  • Arlene C. Seña,
  • Corbin D. Jones

Journal volume & issue
Vol. 17, no. 4

Abstract

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Background Early in the pandemic, transmission risk from asymptomatic infection was unclear, making it imperative to monitor infection in workplace settings. Further, data on SARS-CoV-2 seroprevalence within university populations has been limited. Methods We performed a longitudinal study of University research employees on campus July-December 2020. We conducted questionnaires on COVID-19 risk factors, RT-PCR testing, and SARS-CoV-2 serology using an in-house spike RBD assay, laboratory-based Spike NTD assay, and standard nucleocapsid platform assay. We estimated prevalence and cumulative incidence of seroconversion with 95% confidence intervals using the inverse of the Kaplan-Meier estimator. Results 910 individuals were included in this analysis. At baseline, 6.2% (95% CI 4.29–8.19) were seropositive using the spike RBD assay; four (0.4%) were seropositive using the nucleocapsid assay, and 44 (4.8%) using the Spike NTD assay. Cumulative incidence was 3.61% (95% CI: 2.04–5.16). Six asymptomatic individuals had positive RT-PCR results. Conclusions Prevalence and incidence of SARS-CoV-2 infections were low; however, differences in target antigens of serological tests provided different estimates. Future research on appropriate methods of serological testing in unvaccinated and vaccinated populations is needed. Frequent RT-PCR testing of asymptomatic individuals is required to detect acute infections, and repeated serosurveys are beneficial for monitoring subclinical infection.