Risk assessment and antibody responses to SARS-CoV-2 in healthcare workers

Front Public Health. 2023 Jul 21:11:1164326. doi: 10.3389/fpubh.2023.1164326. eCollection 2023.

Abstract

Background: Preventing infection in healthcare workers (HCWs) is crucial for protecting healthcare systems during the COVID-19 pandemic. Here, we investigated the seroepidemiology of SARS-CoV-2 in HCWs in Norway with low-transmission settings.

Methods: From March 2020, we recruited HCWs at four medical centres. We determined infection by SARS-CoV-2 RT-PCR and serological testing and evaluated the association between infection and exposure variables, comparing our findings with global data in a meta-analysis. Anti-spike IgG antibodies were measured after infection and/or vaccination in a longitudinal cohort until June 2021.

Results: We identified a prevalence of 10.5% (95% confidence interval, CI: 8.8-12.3) in 2020 and an incidence rate of 15.0 cases per 100 person-years (95% CI: 12.5-17.8) among 1,214 HCWs with 848 person-years of follow-up time. Following infection, HCWs (n = 63) mounted durable anti-spike IgG antibodies with a half-life of 4.3 months since their seropositivity. HCWs infected with SARS-CoV-2 in 2020 (n = 46) had higher anti-spike IgG titres than naive HCWs (n = 186) throughout the 5 months after vaccination with BNT162b2 and/or ChAdOx1-S COVID-19 vaccines in 2021. In a meta-analysis including 20 studies, the odds ratio (OR) for SARS-CoV-2 seropositivity was significantly higher with household contact (OR 12.6; 95% CI: 4.5-35.1) and occupational exposure (OR 2.2; 95% CI: 1.4-3.2).

Conclusion: We found high and modest risks of SARS-CoV-2 infection with household and occupational exposure, respectively, in HCWs, suggesting the need to strengthen infection prevention strategies within households and medical centres. Infection generated long-lasting antibodies in most HCWs; therefore, we support delaying COVID-19 vaccination in primed HCWs, prioritising the non-infected high-risk HCWs amid vaccine shortage.

Keywords: COVID-19; SARS-CoV-2; antibodies; healthcare workers; household; occupational; spike protein.

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibody Formation
  • BNT162 Vaccine
  • COVID-19 Vaccines
  • COVID-19* / epidemiology
  • ChAdOx1 nCoV-19
  • Health Personnel
  • Humans
  • Immunoglobulin G
  • Pandemics
  • Risk Assessment
  • SARS-CoV-2*
  • Seroepidemiologic Studies

Substances

  • COVID-19 Vaccines
  • BNT162 Vaccine
  • ChAdOx1 nCoV-19
  • Immunoglobulin G

Grants and funding

The Influenza Centre was supported by the Trond Mohn Stiftelse (TMS2020TMT05), the Ministry of Health and Care Services, Norway; Helse Vest (F-11628, F-12167, and F-12621), the Norwegian Research Council Globvac (284930); the European Union (EU IMI115672, FLUCOP, IMI2 101007799 Inno4Vac, H2020 874866 INCENTIVE, H2020 101037867 Vaccelerate); the Faculty of Medicine, University of Bergen, Norway; and Nanomedicines Flunanoair (ERA-NETet EuroNanoMed2 i JTC2016). RUHS/FHU receives support from Trond Mohn stiftelsen (TMS). AB and M-CT received open research fellowships and mobility grants from the University of Bergen, Norway. AB received a mobility grant from The National Graduate School in Infection Biology and Antimicrobials (or IBA) and a project grant from Pasteur legatet & Thjøtta's legat (101563), University of Oslo, Norway.