Serum prevalence of anti-SARS-CoV-2 antibody in a population of health care and administrative workers in a hospital in Tuscany (Italy).

Introduction: the challenges due to COVID-19 pandemic forced scientific community to focus their efforts to improve diagnosis and management of patients. The recognized gold standard for the diagnosis is the reverse transcription polymerase chain reaction (RT-PCR) on orofaringeal and nasal swabs. Recently, the antibody detection surge to attention with the aim of estimating the epidemiological impact of the pandemic. Methods: the Screen Test COVID-19 2019-nCov IgG/IgM (Screen Italia, Perugia, Italy) an immunochromatographic lateral flow test has been used to assess the immunological status of 356 asymptomatic healthcare and administrative workers of our hospital. Results: only 26 (7.3%) of the screened subjects was positive for IgM and/or IgG anti SARS-CoV-2 virus although the beginning of the epidemic in Tuscany can be dated two months before. The RT-PCR performed on these samples revealed that only 5 (19%) of them were positive for viral RNA on orofaringeal swab. Conclusions: antibody detection will be of great value in the near future to assess global pandemic impact on population and to drive health policy for the lock down release.