AUTHOR=Bansal Amit , Trieu Mai-Chi , Mohn Kristin G. I. , Madsen Anders , Olofsson Jan Stefan , Sandnes Helene Heitmann , Sævik Marianne , Søyland Hanne , Hansen Lena , Onyango Therese Bredholt , Tøndel Camilla , Brokstad Karl Albert , Bergen COVID-19 research group , Syre Heidi , Riis Åse Garløv , Langeland Nina , Cox Rebecca Jane , Amdam Håkon , Bredholt Geir , Ertesvåg Nina Urke , Fjellveit Elisabeth Berg , Lartey Sarah , Grøvan Fredrik , Bartsch Hauke , Kuwelker Kanika , Vahokoski Juha , Kittang Bård , Dagrun Waag Linchausen , Blomberg Bjørn , Zhou Fan TITLE=Risk assessment and antibody responses to SARS-CoV-2 in healthcare workers JOURNAL=Frontiers in Public Health VOLUME=11 YEAR=2023 URL=https://www.frontiersin.org/journals/public-health/articles/10.3389/fpubh.2023.1164326 DOI=10.3389/fpubh.2023.1164326 ISSN=2296-2565 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.