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 ospitals are one of the groups who are at a high rate of exposure to covid19 patients. the detection of antibodies is useful and helps diagnose late or recent sarscov2 infection. most children may present with asymptomatic or mild sarscov2 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 sarscov2 in mofid children's hospital staff. methods: this crosssectional 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 covid19 by polymerase chain reaction (pcr) and/or ct scan. besides, 140 (29.4%) of them were positive for igm and/or igg sarscov2 antibodies. conclusions:the seropositivity of antibodies against sarscov2 among children's hospital staff was higher than expected. approximately 5% of the participants were diagnosed as definitive positive covid19 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.