Severe cases of seasonal influenza and detection of seasonal A(H1N2) in Russia in 2018–2019

Data obtained from monitoring cases of severe influenza, cases of vaccinated individuals, and unique cases were used to describe influenza viruses that circulated in Russia in the 2018–2019 epidemic season. A high proportion of the mutations D222G/N in A(H1N1)pdm09 HA was detected in fatal cases. Viruses of the B/Victoria lineage with deletions in HA were detected in Russia, and a reassortant seasonal influenza A(H1N2) virus was identified. A C-terminal truncation in the NS1 protein was detected in a substantial proportion of A(H3N2) viruses.