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Introduction. The surveillance of influenza viruses in ARVI structure and study of their properties in epidemic season 2019–2020 in Russian Federation are actual for investigations due to tasks of Global Influenza Strategy initiated by WHO in 2019.Material and methods. The data of epidemiological surveillance on influenza- and ARVI-associated morbidity and hospitalization in different age groups of population were analyzed; virological, genetic and statistical methods were used.Results. Preschool children were involved in epidemic the most. Meanwhile, the highest rate of hospitalization was observed in patients of 18–40 years old. Influenza A(H1N1)pdm09 virus dominated in etiology of ARVI in hospitalized patients and pneumonia. The role of respiratory viruses in severe cases of pneumonia and bronchoalveolar syndrome in children was shown. The differences in spectrum of circulating viruses caused ARVI in different regions of Russia were found. Influenza A(H1N1)pdm09 and B/Victoria-like viruses were the main etiological agents that caused of epidemic; its activity among all ARVI was 7.3 and 8.0%, respectively. The differences in antigenic properties of influenza A(H3N2) and B epidemic strains compared to vaccine viruses were found. The populations of epidemic strains were presented by following dominant genetic groups: 6B1.A5/183P for A(H1N1)pdm09, 3С.2а1b+137F for A(H3N2) and V1A.3 line B/Victoria-like for B viruses. The good profile of epidemic strains susceptibility to anti-neuraminidase inhibitors has been saved. The most of the studied influenza strains had the receptor specificity characteristic of human influenza viruses.Conclusions. Obtained results identified the peculiarities of viruses caused the influenza and ARVI in epidemic season 2019–2020 in different regions of Russia. These results suggested the important role of influenza A(H1N1) pdm09 in severe cases and pneumonia in adults 18–40 years old. The continuing drift in influenza viruses was found, which, apparently, could not but affect the efficacy of vaccine prophylaxis and was also considered in the recommendations of WHO experts on the composition of influenza vaccines for the countries of the Northern Hemisphere in the 2020–2021 season.

Институт вирусологии им. Д. И. Ивановского, ФГБУ «НИЦ эпидемиологии и микробиологии имени почетного академика Н. Ф. Гамалеи» Минздрава России, Москва 2 «Инфекционная клиническая больница №1» Департамента Здравоохранения г. Москвы Активность вирусов гриппа в сезон 2017-2018 гг. в России и странах Северного полушария: конфликт по В-вирусному компоненту вакцин Резюме Актуальность. Вирусы гриппа, обладая чрезвычайно высокой изменчивостью генома и существенной экологической пластичностью, продолжают сохранять потенциальную угрозу биологической безопасности человечества. Цель работы-анализ особенностей эпидемического сезона 2017-2018 гг. Материалы и методы. Сбор данных по заболеваемости и лабораторной диагностике гриппа и ОРВИ осуществлялся в рамках эпидемиологического надзора за циркуляцией вирусов гриппа в РФ. Период наблюдения составил с 40 недели (октябрь) 2017 г. по 25 неделю (июнь) 2018 г. Типирование изолятов проводили в реакции торможения гемагглютинирующей активности (РТГА) по общепринятой методике с диагностическими сыворотками к эталонным и эпидемическим вирусам гриппа. Результаты и обсуждение. Представлены особенности циркуляции вирусов гриппа с октября 2017 г. по май 2018 г. на отдельных территориях России, сотрудничающих с Институтом вирусологии им. Д. И. Ивановского. Эпидемический сезон имел свои особенности: отсроченная и длительная активность трех вирусов гриппа, долевое участие которых было практически равнозначным, с некоторым доминированием к концу сезона вируса гриппа A(H1N1)pdm09. Показатели заболеваемости по совокупному населению были сравнимы с прошлым эпидемическим сезоном в тоже время заболеваемость у школьников была значительно выше. Число госпитализаций и летальных случаев было меньше и в основном их регистрировали в возрастной группе 65 лет и старше. У пациентов с тяжелой острой респираторной инфекцией (ТОРИ) более часто детектировали грипп A(H1N1)pdm09 (58%). Вирусы гриппа A(H1N1)pdm09 и A(H3N2) имели близкое родство со штаммами, входившими в состав гриппозных вакцин, в тоже время, 96% выделенных штаммов вируса гриппа В принадлежали другой эволюционной линии. Эпидемические штаммы проявили чувствительность к препаратам с антинейраминидазной активностью, за исключением 5 штаммов вируса гриппа A(H1N1)pdm09, выделенных от беременных. Выводы. Долевое участие возбудителей ОРВИ не гриппозной этиологии было сравнимо с предыдущими эпидемическими сезонами. Представлены рекомендации экспертов

The article presents the features of the influenza virus circulation for the period from October 2016 to May 2017 in some territories of Russia collaborating with the D.I. Ivanovsky Institute of Virology, Federal State Budgetary Institution “N.F. Gamaleya Federal Research Centre for Epidemiology and Microbiology”, Ministry of Health of the Russian Federation. One of the 2016-2017 season’s peculiarities in Russia and countries of the Northern hemisphere was the earlier start of an increase in ARD morbidity with peak indexes reached towards the end of December 2016 - January 2017. First, influenza A(H3N2) virus was predominant; then, it was followed by influenza B virus activity observed until the end of the season. The indexes of morbidity were higher than in the previous season, while the rates of hospitalization and mortality were lower, lethal cases being detected in persons 65 years old and older. Epidemic strains of influenza A(H3N2) virus belonged to 3c.2a genetic group, reference strain A/Hong Hong/4408/2014, and its subgroup 3c.2a1, reference A/Bolzano/7/2016, that are antigenically similar. Strains of influenza B virus were antigenically similar to the B/Brisbane/60/2008 vaccine virus. Strains were sensitive to oseltamivir and zanamivir. The share participation of non-influenza ARI viruses was similar to preliminary epidemic seasons. WHO has issued recommendations for influenza virus vaccines composition for 2017-2018 for the Northern hemisphere.

BACKGROUND: The article presents the results of studying the effectiveness of anti-influenza drugs in Russia in the period 20172020. The sensitivity of circulating strains of influenza viruses A(H1N1)pdm09, A(H3N2) and B to neuraminidase inhibitors oseltamivir, zanamivir and rimantadine was determined. The analysis of scientific articles by both domestic and foreign researchers on new promising chemotherapy drugs for influenza viruses was carried out. AIMS: study of the sensitivity of influenza viruses circulating strains to specific anti-influenza drugs in the framework of monitoring in the period 20172020. MATERIALS AND METHODS: The study was conducted within the framework of epidemiological surveillance of the influenza viruses circulation using the collection of the influenza etiology and epidemiology laboratory with the following criteria for selecting strains isolated from pregnant women, patients with complicated flu infection and severe acute respiratory infection (SARI), lethal outcomes, as well as patients undergoing treatment with specific drugs. Virological, immunological, and molecular genetic methods were used in the study, and following drugs substances were used: oseltamivir carboxylate, zanamivir, and rimantadine. RESULTS: For the period 20172020, the sensitivity of 541 influenza A and B viruses epidemic strains to anti-influenza drugs was studied. Most of the studied strains remained sensitive to neuraminidase inhibitors. The exceptions were: in 2017/2018 5 strains of the influenza A(H1N1)pdm09 virus resistant to oseltamivir and 2 strains of the influenza B virus, one with reduced sensitivity to oseltamivir, the second to zanamivir; in 2019/2020 influenza A(H1N1)pdm09 virus strain with reduced sensitivity to both drugs. In the 2018/2019 season, an influenza A/Moscow/246/2018 A(H1N1)pdm09 strain was found to be sensitive to rimantadine. CONCLUSIONS: The main and most common genetic markers of influenza viruses resistance to specific drugs are: for oseltamivir substitution H274Y in the influenza A(H1N1)pdm09 virus NA; for rimantadine substitution S31N in the influenza A(H1N1)pdm09 and A(H3N2) viruses M2 protein. Taking into account the low frequency of strains with reduced sensitivity to drugs with antineuraminidase activity, can confidently approve that they remain the drugs of choice for the treatment and prevention of influenza infection.