The Epidemic Process of Influenza and ARVI in Long-Term Dynamics and in the Context of the COVID‑19 Pandemic in Ekaterinburg

Abstract

Introduction. Knowledge of the patterns of development of the epidemic process of influenza and other acute respiratory viral infections in the long-term dynamics allows you to obtain important information for the prompt resolution of issues related to the prevention of these infections. Almost unstudied is the manifestation of the epidemic process of influenza in the conditions of circulation of parasitic systems of influenza viruses and COVID‑19. The aim of this work is to assess the manifestation of the epidemic process of influenza and other viral respiratory infections in long-term dynamics and in the context of the pandemic extension of a new coronavirus infection. Materials and methods. Epidemiological analysis was subject to the materials of the Federal Statistical Observation (f. № 2 “Information on Infectious and Parasitic Diseases”); reports on the results of prophylactic vaccinations against influenza (f. № 5); reports of medical organizations of Ekaterinburg on registered infectious diseases. A retrospective analysis of the total incidence of influenza and acute respiratory viral infection (ARVI) was carried out on registered cases in 1996–2021, and COVID‑19 in 2020–2021. The results were statistically processed using the Microsoft Office Excel 2013 software package. Results. The manifestation of the epidemic process of influenza and ARVI in 1996–2021 in Ekaterinburg and the Sverdlovsk Region varied significantly over the years. In the period from 1996 to 2008, the epidemic process was due to the circulation of A1, A3 and B influenza viruses and was rated as stable. The appearance of the A(H1N1)09 virus reassortant in 2009 significantly changed the trend of the epidemic process towards its intensification (t = 265.6, p < 0.001). Among the sick, the proportion of the child population was 69.9 % and adults 30.1 %. During the COVID‑19 pandemic, the incidence of influenza and ARVI in 2021 was significantly higher than in 2019 (t = 55.9, p < 0.001). The seasonality of influenza in 2021 has also changed, with a maximum rise in incidence in October. Discussion. The epidemiological process of influenza and ARVI in the long-term dynamics was continuous and was caused by a heterogeneous population of circulating viruses, the incidence of all age groups of the population with the dominance of children. During the coronavirus pandemic, an intensification of the epidemic process of influenza and ARVI and a shift in seasonality to September were noted, which may be a consequence of the circulation of two parasitic systems. Conclusion. A trend of intensification of the epidemic process of influenza since 2009, due to the circulation of influenza A(H1N1)09 virus in the human population, has been noted. During the COVID‑19 pandemic, there was an increase in the number of cases of influenza and SARS and a shift in the seasonality of these infections by September 2021.

For citation
Slobodenyuk AV, Bessergeneva IK, Kosova AA. The epidemic process of influenza and ARVI in long-term dynamics and in the context of the COVID‑19 pandemic in Ekaterinburg. Bulletin of USMU. 2023;(3):61–73. (In Russ.). EDN: https://elibrary.ru/SAGJES.