Formation of Herd Immunity to SARS-CoV-2 in the Population of Moscow

Abstract

Relevance . The research of the dynamics of population immunity formation is an important component of epidemiological surveillance, especially during the pandemic period. Identifying the features of the course of the epidemic process of a particular infection provides an opportunity to make the right decisions both in the fight against the disease and in its prevention. Aims . Evaluate the dynamics of the formation of collective immunity in the population of the city of Moscow. Materials & Methods. The presence of immunity in the population was assessed by immunochemiluminescent analysis of blood serum of patients for the presence of antibodies IgM and IgG to SARS-CoV-2. Results . During the analysis of the annual dynamics of IgM detection, a gradual decrease in this indicator was recorded. The dynamics of the combined detectability of IgM/IgG has a wave-like course. It should be noted that the curves of the dynamics of the IgM detectability and the combined IgM/IgG detectability reflect multidirectional trends: the summer rise in the IgM detectability coincides with the fall and the lowest values of the IgM/IgG detectability indicator. Afterwards, the decrease in the IgM detectability is accompanied by an increase in the combined IgM / IgG detectability. Detectability of IgG has a pronounced tendency to rise with short time intervals of decline. In the first three months of testing, a gradual decrease in detectability was recorded from 15.2 to 10.8%. However, since August, there has been a new increase in detectability of IgG to 45.5% in marth and subsequent stabilization in the range of 44.3–45.5%. Conclusions. The level of seroprevalence for the period of May 2021 is 44.3%. Detection during screening of patients with IgM and partially with a combination of IgM / IgG may indicate the presence of a significant hidden component of the epidemic process, which may lead to an increase in morbidity.