SARS-CoV-2 seroprevalence and antibodies persistence among health care workers after the first COVID-19 wave in nine hospitals in Western France

Objectives: To estimate the SARS-CoV-2 IgG seroprevalence rate in healthcare workers (HCWs) from Western France after the first 2020 wave, its determinants and the kinetics of total SARS-CoV-2 antibodies.

Patients and methods: Overall, 9,453 HCWs responded to a self-questionnaire and underwent a lateral flow immunoassay to assess SARS-CoV-2 IgG presence. For 72 HCWs who tested positive, total anti-nucleocapsid antibodies were assessed at day 0, 30, and 90.

Results: SARS-CoV-2 IgG seroprevalence rate was 1.06 % [0.86 %-1.27 %]. Factors associated with IgG presence were gender, performing upper respiratory tract samples, contact with HCWs or household members diagnosed with COVID-19. Total antibodies decreased between day 0 and day 90, with anosmia or ageusia, and were higher in HCWs older than 50 years.

Conclusion: We reported a low prevalence rate of IgG and identified several risk factors associated with its presence and persistence of total antibodies. Additional studies are needed to confirm these observations.