Seroprevalence of anti-sars-cov-2 antibodies among healthcare professionals in Moscow in april-december 2020

ABSTRACT

We evaluated humoral immunity (presence of specific IgM and IgG) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among healthcare professionals providing inpatient care for individuals with COVID-19. Objective. To detected and measure the level of anti-SARS-CoV-2 antibodies in healthcare professionals and to identify how many of them contacted with COVID-19 patients, including those who had asymptomatic or subclinical disease. Materials and methods. Anti-SARS-CoV-2 antibodies were detected using enzyme-linked immunosorbent assay (ELISA) with the ‘SARS-CoV-2-ELISA-Vector’ kit for IgG (State research Center of Virology and Biotechnology ‘Vector’) and ‘SARS-CoV-2-IgG- ELISA-BEST’ and ‘SARS-CoV-2-IgМ-ELISA-BEST’ kits for IgM and IgG (Vector-Best LLC). Samples were collected in several healthcare institutions of Moscow and in G.N.Gabrichevskiy Moscow Research Institute of Epidemiology and Microbiology. A total of 24,373 serum specimens from 74 healthcare institutions were tested. All study participants filled in special questionnaires. Results. Among 24,373 healthcare professionals tested in this study, 5,382 people were IgG-positive to SARS-CoV-2 (seroprevalence index 22.1%). The seropositivity rate was 21.5% in senior medical staff, 22.2% in nursing professionals, and 22.8% in medical assistants/technicians. We found that the proportion of SARS-CoV-2 seropositive individuals had changed over time, gradually increasing from 17.9% in April 2020 to 37.6% in December 2020. The proportion of SARS-CoV-2 seropositive people doubled among senior medical staff and nursing professionals during the year. The proportion of individuals with asymptomatic or subclinical COVID-19 was 13.8%. Conclusion. The methodological approaches used in this study allowed us to assess the humoral immunity to SARS-CoV-2 among healthcare professionals in Moscow. Our findings can be used for further improvement of anti-epidemic measures in healthcare institutions. © 2021, Dynasty Publishing House. All rights reserved.