A dramatic increase of influenza activity in Russia since week 3 of 2016 significantly differs from previous seasons in terms of the incidence of influenza and acute respiratory infection (ARI) and in number of lethal cases. We performed antigenic analysis of 108 and whole‐genome sequencing of 77 influenza A(H1N1)pdm09 viruses from Moscow and Saint Petersburg. Most of the viruses were antigenically related to the vaccine strain. Whole‐genome analysis revealed a composition of specific mutations in the internal genes (D2E and M83I in NEP, E125D in NS1, M105T in NP, Q208K in M1, and N204S in PA‐X) that probably emerged before the beginning of 2015/2016 epidemic season.
Целью работы было сравнение показателей интенсивности эпидемии гриппа, вызванной штаммами вирусов гриппа А(H3N2) и В, в сезон 2014-2015 гг. с предшествующей эпидемией 2013-2014 гг. Особое внимание уделено летальным исходам от гриппа. Использована база данных НИИ гриппа по еженедельной заболеваемости, госпитализации, летальным исходам от гриппа и ОРЗ в различных возрастных группах населения 59-ти наблюдаемых городов, расположенных в семи Федеральных округах Российской Федерации. По сравнению с эпидемией 2014 г. эпидемия гриппа в 2014-2015 гг. началась раньше (в декабре) и распространялась, в основном, с запада на восток-из Европы по территории России в восточном направлении. Показатели интенсивности эпидемии 2015 г., в сравнении с предыдущей, были выше в отношении распространенности по округам, городам и вовлеченности возрастных групп населения (кроме детей до 2-х лет). Показатели заболеваемости на пике эпидемии, средней продолжительности эпидемии, уровней заболеваемости населения в городах (особенно среди детей 7-14 лет и взрослого населения) были выше, чем в предыдущем сезоне. Участились и случаи госпитализации с гриппом и OPВИ среди лиц старше 65 лет (в 1.4 раза), среди госпитализированных повысилась доля больных с диагнозом «грипп» (в 2.7 раза) и число летальных исходов от лабораторно подтвержденного гриппа (в 1.8 раза). Штамм пандемического вируса гриппа, A(H1N1)pdm09, хотя и не был основным возбудителем эпидемии 2015 г., попрежнему стал основной причиной летальных исходов от гриппа (в 45.5% всех случаев); причем случаи смерти, ассоциированные с этим штаммом, регистрировали только на европейской территории России при спорадическом уровне его распространения.
Influenza circulation was substantially reduced after March 2020 in the European region and globally due to the wide introduction of non-pharmaceutical interventions (NPIs) against COVID-19. The virus, however, has been actively circulating in natural reservoirs. In summer 2021, NPIs were loosened in Russia, and influenza activity resumed shortly thereafter. Here, we summarize the epidemiological and virological data on the influenza epidemic in Russia in 2021–2022 obtained by the two National Influenza Centers. We demonstrate that the commonly used baseline for acute respiratory infection (ARI) is no longer sufficiently sensitive and BL for ILI incidence was more specific for early recognition of the epidemic. We also present the results of PCR detection of influenza, SARS-CoV-2 and other respiratory viruses as well as antigenic and genetic analysis of influenza viruses. Influenza A(H3N2) prevailed this season with influenza B being detected at low levels at the end of the epidemic. The majority of A(H3N2) viruses were antigenically and genetically homogenous and belonged to the clade 3C.2a1b.2a.2 of the vaccine strain A/Darwin/9/2021 for the season 2022–2023. All influenza B viruses belonged to the Victoria lineage and were similar to the influenza B/Austria/1359417/2021 virus. No influenza A(H1N1)pdm09 and influenza B/Yamagata lineage was isolated last season.
Aim. To assess the intensity of the epidemic process in each of the five waves of COVID-19 in Russia.Materials and methods. The data on morbidity, hospitalization and deaths from COVID-19 of the population as a whole and by age groups from 48 (in the I rise) to 54 cities (in the V wave) and data from the website of the Russian consortium for sequencing coronavirus genomes were analyzed.Results. The nature of the course of the first 5 waves in the incidence of COVID-19 in Russia remains undulating. The waves in morbidity began in megacities, and the direction of spread across the FD differed in different waves of morbidity. The results of gene sequencing showed the participation of the main genovariants of the coronavirus in the etiology of diseases up to 3-4 waves. Some genovariants identified earlier received maximum distribution in the following wave. In Russia, the European descendants of the Wuhan strain (74.4%) were dominant in the I wave in morbidity, in the II wave – its daughter genovariants (68.5%), in the III – AY.122 (80.1%), in the IV – AY.122 (84.7%) and in the V wave – Omicron (76.7%).Conclusions. The features of each wave in the incidence of COVID-19 depended on the properties of the dominant genovariants: their ability to transmit from person to person and virulence. The rate of spread of the epidemic by FD, the susceptibility of all age groups and the intensity of epidemics were maximal during the period of the V wave in morbidity with the Omicron gene variant. Mortality was minimal in the I wave of morbidity, maximal in the IV with AY.122 strains and low in the V wave with Omicron genovariants. The influence of the season of the year was manifested in the summer season by an increase in the incidence of COVID-19 earlier in the Russian Federation as a whole (immediately after megacities) than in most federal districts, but with a lower incidence.
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