Detection of antibodies to SARS-CoV-2 in healthcare professionals of the National Center during the COVID-19 pandemic (April-June 2020)

Objective. To identify IgG antibodies to SARS-CoV-2 in healthcare professionals of the National Medical Research Center for Obstetrics, Gynecology and Perinatology during the quarantine from April to June 2020. Materials and methods. The study included 1589 healthcare workers: 1293 professionals of ‘green zone’ and 926 medical staff of‘red zone’. IgG antibodies to SARS-CoV-2 in blood serum were determined using SARS-CoV-2-IgG- ELISA kits (National Hematology Research Center, Russia). SARS-CoV-2 RNA was extracted from nasopharyngeal swabs using the kit PROBA-NK(DNA-technology, LLC, Russia). The virus was identified by RT-PCR using SARS-CoV-2/SARS-CoVMultiplex REAL-TIME PCR Detection Kit (DNA-technology, LLC, Russia). Results. IgG antibodies to SARS-CoV-2 were detected in 141 healthcare workers (8.9%), controversial results were revealed in 2professionals, and 1445 (90.9%) workers had no antibodies, including 46 (3.2%) people who had the clinical symptoms of acute respiratory viral disease (ARVI) and identified SARS-CoV-2 RNA. Among healthcare workers with antibodies, the clinical symptoms of ARVI were revealed in 129 (91.5%) workers, they were also detected SARS- CoV-2 RNA; 23 (17.8%) people had clinical symptoms of ARVI but SaRS- CoV-2 RNA was not extracted; 12 (8,5%) workers had neither clinical symptoms of ARVI nor detected SARS- CoV-2 RNA. Conclusion. The presence of IgG antibodies and the absence of SARS-CoV-2 RNA in the nasopharyngeal swab as well as clinical symptoms of the disease may be suggestive of the fact that the worker had this disease; the presence of IgG antibodies and the absence of SARS- CoV-2 RNA as well as clinical symptoms of the disease may be suggestive of the fact that the worker has this disease.

COVID-19, COVID-19, IgG antibodies to SARS-CoV-2, immune reactivity