Analysis of SARS-CoV-2 seroprevalence among the population of the Vladimir Region during the COVID-19 epidemic

Objective. To estimate the level of seroprevalence in the population of the Vladimir Region during the COVID-19 epidemic. Materials and methods. Work was done as part of the first stage of the program to assess herd immunity to SARS-CoV-2 among the population of the Russian Federation according to the common methodology developed by the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being with the participation of the Pasteur Research Institute of Epidemiology and Microbiology. Volunteers were selected using questionnaires and randomization. The analysis included the results of a survey of2,798 volunteers distributed in 7 age groups. The level of IgG specific to SARS- CoV-2 nucleocapsid was determined by enzyme immunoassay. Results. The level of seroprevalence in the population was 10.7%, with a maximum of 25.1% in children aged 1-6 years and a minimum of 7.6% in people aged 18-29 years. No statistically significant differences were found between men and women in indicators. Specific antibodies were detected in 57.1% of the patients who had experienced COVID-19. Contact with a COVID-19 patient was accompanied by seroconversion 1.5 times more often than the population average. Seroconversion was 42.3% in asymptomatic individuals with positive PCR. Among the seropositive volunteers, the proportion of asymptomatic infection amounted to as much as 87.6%. Conclusion. Low seroprevalence in the population contributed to the emergence of the second wave of COVID-19.

SARS-CoV-2, coronaviruses, SARS- CoV-2, morbidity, seroprevalence, Vladimir Region, population