Prevalence of SARS-CoV-2 Specific Antibodies in the Staff of a Children's Hospital, in Tehran, Iran

Background: In December 2019, a new coronavirus appeared in China, as a cause of acute respiratory disease. Healthcare Workers (HCWs) in children's hospitals are one of the groups who are at a high rate of exposure to COVID-19 patients. The detection of antibodies is useful and helps diagnose late or recent SARS-CoV-2 infection. Most children may present with asymptomatic or mild SARS-CoV-2 infection and can be silent sources of infection in the community and hospitals. Objectives: This study was conducted to determine the antibodies (IgM and IgG) against SARS-CoV-2 in Mofid children's hospital staff. Methods: This cross-sectional study evaluated 475 staff from Mofid children's hospital from April 20 to May 5, 2020, in Tehran. We collected blood samples for the antibody assay with a rapid test kit. A questionnaire was used to collect demographic and clinical data. Results: Of 475 staff who participated in this study, 25 (5.3%) were diagnosed with COVID-19 by Polymerase Chain Reaction (PCR) and/or CT scan. Besides, 140 (29.4%) of them were positive for IgM and/or IgG SARS-CoV-2 antibodies. Conclusions: The seropositivity of antibodies against SARS-CoV-2 among children's hospital staff was higher than expected. Approximately 5% of the participants were diagnosed as definitive positive COVID-19 cases by PCR and/or CT scan, but 29.4% of them were seropositive. The difference is a warning, as it shows seropositive people could be silent sources of transmission during asymptomatic infection.