Large variation in anti-SARS-CoV-2 antibody prevalence among essential workers in Geneva, Switzerland

Stringhini, Silvia; Zaballa, María-Eugenia; Pullen, Nick; de Mestral, Carlos; Perez-Saez, Javier; Dumont, Roxane; Picazio, Attilio; Pennacchio, Francesco; Dibner, Yaron; Yerly, Sabine; Baysson, Helene; Vuilleumier, Nicolas; Balavoine, Jean-François; Bachmann, Delphine; Trono, Didier; Pittet, Didier; Chappuis, François; Kherad, Omar; Kaiser, Laurent; Azman, Andrew S.; Guessous, Idris

Limited data exist on SARS-CoV-2 infection rates across sectors and occupations, hindering our ability to make rational policy, including vaccination prioritization, to protect workers and limit SARS-CoV-2 spread. Here, we present results from our SEROCoV-WORK + study, a serosurvey of workers recruited after the first wave of the COVID-19 pandemic in Geneva, Switzerland. We tested workers (May 18—September 18, 2020) from 16 sectors and 32 occupations for anti-SARS-CoV-2 IgG antibodies. Of 10,513 participants, 1026 (9.8%) tested positive. The seropositivity rate ranged from 4.2% in the media sector to 14.3% in the nursing home sector. We found considerable within-sector variability: nursing home (0%–31.4%), homecare (3.9%–12.6%), healthcare (0%–23.5%), public administration (2.6%–24.6%), and public security (0%–16.7%). Seropositivity rates also varied across occupations, from 15.0% among kitchen staff and 14.4% among nurses, to 5.4% among domestic care workers and 2.8% among journalists. Our findings show that seropositivity rates varied widely across sectors, between facilities within sectors, and across occupations, reflecting a higher exposure in certain sectors and occupations.