Age features of immunity to SARS-CoV-2 of metropolis population in the dynamics

Introduction. Large-scale vaccination is considered to be the most effective method of protection from infectious diseases. Vaccination implementation helps to increase population (community) immunity. The study of formation features of population immunity remains relevant task for understanding the course of epidemic process. Objective. To assess the dynamics and age features of community immunity formation to SARS-CoV-2 of metropolis population. Material and methods. A retrospective epidemiological study of serological screening was conducted. Results of laboratory examination of 2 903 747 patients (1 050 680 (36.2%) men and 1 853 067 (63.8%) women) for IgM and IgG antibodies to SARS-CoV-2 for 30 months were analyzed. Results. Decrease of IgM detection was found in two centralized laboratories during pandemic height. Combined detection of IgM/IgG in both laboratories had a similar undulating type of course. IgG detection has increased over time equivalently in each laboratory. There was an increase in the number of patients with high antibodies while assessing age-specific features of community immunity with age increase in 2020 and 2021 yrs. However, the trend has changed in 2022 yr. and there are no significant differences in the ratio of different age groups of patients with various rate of antibodies. Such changes happened in metropolis when new, more contagious version of SARS-CoV-2, namely Omicron, occurred. Conclusions. The formation of a pronounced immune response in different age groups of patients of metropolis, especially in young population, most probably, caused by distribution of new version of SARS-CoV-2, namely Omicron, that may have affected secondary immune response activation in previously vaccinated or recovering patients in the city. © 2024, Media Sphera Publishing Group. All rights reserved.