Estimating the prevalence of SARS-COV-2 antibody seropositivity among health care workers (HCWs) is crucial. In this study the seroprevalence of anti-SARS-COV-2 antibodies among HCWs of five hospitals of Tehran-Iran with high COVID-9 patient’s referrals was assessed

HCWs from public and private hospitals were included and were asked questions on their demographic characteristics, medical history, hospital role and usage of personal protective equipment (PPE). Seroprevalence was estimated on the basis of ELISA test results (IgG and IgM antibodies in blood samples) and adjusted for test performance

Among the 2065 participants, 88.4% and 11.6% HCWs were recruited from the public and private hospitals, respectively. The overall test-performance adjusted seroprevalence estimate among HCWs was 22.6 (95% CI 20.2-25.1) and it was higher in private hospitals (37.0%; 95% CI 28.6-46.2) than public hospitals (20.7%; 95% CI 18.2-23.3). PPE usage was significantly higher among HCWs of public versus private hospitals (66.5% vs. 20.0%). Test-adjusted seroprevalence estimates were highest among assistant nurses and nurses, and lowest among janitor/superintendent categories.

Seroprevalence of SARS-COV-2 among HCWs depends on hospital type, hospital department, and hospital role. The PPE usage was especially suboptimal among HCWs in private hospitals. Continued effort in access to adequate PPE is warranted.