SARS-CoV-2 specific serological pattern in healthcare workers of an Italian COVID-19 forefront hospital

Background: COVID-19 is an infectious disease caused by a novel coronavirus (SARS-CoV-2). The immunopathogenesis of the infection is currently unknown. Healthcare workers (HCWs) are at highest risk of infection and disease. Aim of the study was to assess the sero-prevalence of SARS-CoV-2 in an Italian cohort of HCWs exposed to COVID-19 patients. Methods: A point-of-care lateral flow immunoassay (BioMedomics IgM-IgG Combined Antibody Rapid Test) was adopted to assess the prevalence of IgG and IgM against SARS-CoV-2. It was ethically approved ("Milano Area 1"Ethical Committee prot. n. 2020/ST/057). Results: A total of 202 individuals (median age 45 years; 34.7% males) were retrospectively recruited in an Italian hospital (Milan, Italy). The percentage (95% CI) of recruited individuals with IgM and IgG were 14.4% (9.6-19.2%) and 7.4% (3.8-11.0%), respectively. IgM were more frequently found in males (24.3%), and in individuals aged 20-29 (25.9%) and 60-69 (30.4%) years. No relationship was found between exposure to COVID-19 patients and IgM and IgG positivity. Conclusions: The present study did show a low prevalence of SARS-CoV-2 IgM in Italian HCWs. New studies are needed to assess the prevalence of SARS-CoV-2 antibodies in HCWs exposed to COVID-19 patients, as well the role of neutralizing antibodies.