Kolosova NP, Boldyrev ND, Svyatchenko SV, Danilenk. An Investigation of Severe Influenza Cases in Russia during the 2022-2023 Epidemic Season and an Analysis of HA-D222G/N Polymorphism in Newly Emerged and Dominant Clade 6B.1A.5a.2a A(H1N1)pdm09 Viruse. Pathogens. 2023 Dec 19;13(1):1
In Russia, during the COVID-19 pandemic, a decrease in influenza circulation was initially observed. Influenza circulation re-emerged with the dominance of new clades of A(H3N2) viruses in 2021-2022 and A(H1N1)pdm09 viruses in 2022-2023. In this study, we aimed to characterize influenza viruses during the 2022-2023 season in Russia, as well as investigate A(H1N1)pdm09 HA-D222G/N polymorphism associated with increased disease severity. PCR testing of 780 clinical specimens showed 72.2% of them to be positive for A(H1N1)pdm09, 2.8% for A(H3N2), and 25% for influenza B viruses. The majority of A(H1N1)pdm09 viruses analyzed belonged to the newly emerged 6B.1A.5a.2a clade. The intra-sample predominance of HA-D222G/N virus variants was observed in 29% of the specimens from A(H1N1)pdm09 fatal cases. The D222N polymorphic variant was registered more frequently than D222G. All the B/Victoria viruses analyzed belonged to the V1A.3a.2 clade. Several identified A(H3N2) viruses belonged to one of the four subclades (2a.1b, 2a.3a.1, 2a.3b, 2b) within the 3C.2a1b.2a.2 group. The majority of antigenically characterized viruses bore similarities to the corresponding 2022-2023 NH vaccine strains. Only one influenza A(H1N1)pdm09 virus showed reduced inhibition by neuraminidase inhibitors. None of the influenza viruses analyzed had genetic markers of reduced susceptibility to baloxavir.
See Also:
Latest articles in those days:
- Emergence of a genetically distinct cluster of influenza A(H3N2) viruses within subclade J.2.2 associated with hospitalization during the 2024-2025 season in Auvergne-Rh?ne-Alpes, France 11 hours ago
- Interaction between DEAD-box RNA helicase 10 and influenza PB1 polymerase selectively regulates influenza A virus replication 11 hours ago
- Genetic Diversity of Clade 2.3.4.4b H5Nx High Pathogenicity Avian Influenza Viruses Detected in Korea During the 2025-2026 Winter Season and Pathogenicity of H5N1 and H5N9 Viruses 11 hours ago
- Update and optimization of a multiplex RT-qPCR assay to overcome diagnostic failure in emerging influenza A(H3N2) subclades J.2 and K (Peru, 2024-2026) 11 hours ago
- Antigenic and structural analysis of the influenza hemagglutinin lateral patch 11 hours ago
[Go Top] [Close Window]


