Эпидемиология и вакцинопрофилактика (Jun 2019)
The Activity of Influenza Viruses during 2017-2018 Season in Russia and Countries of the Northern Hemisphere: Conflict by the B-virus Vaccine Component
Abstract
Relevance. Influenza viruses, having an extremely high variability of the genome and significant environmental plasticity, continue to maintain a potential threat to the biological safety of mankind. The purpose Aims of the work is to analyze the features of the epidemic season of2017-2018.Materials and methods. The collection of data on the incidence and laboratory diagnosis of influenza and ARVI was carried out in the framework of the epidemiological surveillance of the circulation of influenza viruses in the Russian Federation. The observation period was from 40 weeks (october) 2017 to 25 weeks (june) 2018. The typing of the isolates was performed in the reaction of inhibition of hemagglutination activity (HI) according to the standard technique with diagnostic sera to reference and epidemic influenza viruses.Results and discussion. The article presents the features of the influenza virus circulation n for the period from october 2017 to may 2018 in some territories of Russia, collaborating with D. I. Ivanovsky Institute of Virology. The epidemic season had its own peculiarities: delayed and long-term activity of three influenza viruses, the share participation of which was almost equal, with some dominance of the influenza A(H1N1)pdm09 virus by the end of the season. Morbidity rates for the total population were comparable with the last epidemic season, meantime the morbidity among schoolchildren was higher. The number of hospitalizations and lethal outcomes was lower and mostly was found in patients of 65 years and older. In patients with severe acute respiratory infection (SARI) influenza A(H1N1)pdm09 was detected more frequently (58%). The influenza A(H1N1)pdm09 and A(H3N2) viruses were antigenically similar to strains included in influenza vaccines, at the same time, 96% of the isolated strains of influenza B virus belonged to a different evolutionary line. Epidemic strains were sensitive to neuraminidase inhibitors, except for 5 strains of influenza A(H1N1)pdm09 virus, isolated from pregnant women.Conclusions. The activity of non- influenza ARI viruses was similar to preliminary epidemic seasons. Recommendations on the influenza vaccines composition for the Northern hemisphere for 2019-2020 season are presented as well.
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