Risk assessment and seroprevalence of SARS-CoV-2 infection in healthcare workers of COVID-19 and non-COVID-19 hospitals in Southern Switzerland.

BACKGROUND

Hospital healthcare workers (HCW), in particular those involved in the clinical care of COVID-19 cases, are presumably exposed to a higher risk of acquiring the disease than the general population.

METHODS

Between April 16 and 30, 2020 we conducted a prospective, SARS-CoV-2 seroprevalence study in HCWs in Southern Switzerland. Participants were hospital personnel with varying COVID-19 exposure risk depending on job function and working site. They provided personal information (including age, sex, occupation, and medical history) and self-reported COVID-19 symptoms. Odds ratio (OR) of seropositivity to IgG antibodies was estimated by univariate and multivariate logistic regressions.

FINDINGS

Among 4726 participants, IgG antibodies to SARS-CoV-2 were detected in 9.6% of the HCWs. Seropositivity was higher among HCWs working on COVID-19 wards (14.1% (11.9-16.5)) compared to other hospital areas at medium (10.7% (7.6-14.6)) or low risk exposure (7.3% (6.4-8.3)). OR for high vs. medium wards risk exposure was 1.42 (0.91-2.22),

INTERPRETATION

SARS-CoV-2 antibodies are detectable in up to 10% of HCWs from acute care hospitals in a region with high incidence of COVID-19 in the weeks preceding the study. HCWs with exposure to COVID-19 patients have only a slightly higher absolute risk of seropositivity compared to those without, suggesting that the use of PPE and other measures aiming at reducing nosocomial viral transmission are effective. Household contact with known COVID-19 cases represents the highest risk of seropositivity.

FUNDING

Henry Krenter Foundation, Ente Ospedaliero Cantonale and Vir Biotechnology.

Informations de copyright

© 2020 The Authors.

Déclaration de conflit d'intérêts

LP, C.S-F and NS report that the work was supported in part by Vir Biotechnology. DC, AL, IB, EC and SJ report that they owns shares of Vir Biotechnology and that the work was supported in part by Vir Biotechnology. FS owns shares of Vir Biotechnology. EB reports other from Gilead Sciences, other from Merck Sharp & Dohme, other from ViiV Healthcare, other from Pfizer, other from Abbvie, other from Sandoz, outside the submitted work. CG reports to be an external scientific consultant of Humabs BioMed SA, outside the submitted work. AC, PF, LE, OG, MU, EA, BFR, IG-S, SJ, FM, GP and TT have nothing to disclose.