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

Abstract

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.