EPIDEMIC SEASON 2021-2022. FREQUENCY OF CO-INFECTION BY RESPIRATORY VIRAL PATHOGENS

Introduction. The main purpose of this work was to determine the characteristics of the circulation of various viral respiratory pathogens during the epidemic season 2021-2022, as well as the frequency of co-infection against the background of SARS-CoV-2 and influenza. Materials and methods. The article uses methods of "traditional" and "hospital" epidemiological surveillance for acute respiratory viral infections. Results and discussion. The epidemic season of 2021-2022 was characterized by the early activity of the influenza A(H3N2) virus, as well as the appearance and rapid spread of a new variant of SARS-CoV-2 (omicron). The dependence on the share of different respiratory pathogens during the epidemic season 2021-2022 was clearly traced: the dominant role belonged to SARS-CoV-2 (18.8%), then to influenza viruses (10.6%) and, finally, to pathogens of other acute respiratory viral infections (0.4%-3.7%). With respect to influenza A(H3N2) and B viruses, heterogeneity of their populations and drift-variability in relation to vaccine strains were noted. The frequency of co-infection with various respiratory pathogens was low: according to "traditional surveillance" - no more than 0.1%, "hospital surveillance" no more than 9.2%. The rationale for updating the composition of influenza vaccines for the countries of the Northern Hemisphere for 2022-2023 season was given.