Rapid spread of influenza A(H1N1)pdm09 viruses with a new set of specific mutations in the internal genes in the beginning of 2015/2016 epidemic season in Moscow and Saint Petersburg (Russian Federation)

Abstract

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.

Molecular characterization of the influenza A(H1N1)pdm09 isolates collected in the 2015‐2016 season and comparison of HA mutations detected in Turkey since 2009

“…Regarding the 2015‐2016 season, subclades 6B.1 and 6B.2 appeared as new clusters in clade 6B. In Turkey, all studied influenza A(H1N1)pdm09 isolates of this season belonged only to 6B.1 as detected in studies by Komissarov et al, Korsun et al, Clark et al, Puig‐Barberà et al, Mohebbi et al Cocirculation of 6B.1 and 6B.2 isolates was also observed in some other studies …”

“…Since emergence in 2009, the genetic makeup of influenza A(H1N1) pdm09 virus has been changing for both to adapt to new hosts and survive in different geographic and seasonal conditions. 18 19 Korsun et al, 20 Clark et al, 21 Puig-Barberà et al, 22 Mohebbi et al 23 Cocirculation of 6B.1 and 6B.2 isolates was also observed in some other studies. [24][25][26][27][28] In the 2009-2010 and 2010-2011 seasons, the HA nucleotide sequence similarity rates between Turkish isolates and the A/ California/07/2009 virus were >98.9% and >98.7%, respectively, 11,12 but the similarity ranging 96.6% to 97.2% we observed in the 2015-2016 season was pointing out a rising divergence from the progenitor virus compared to the previous seasons.…”

“…However, WHO recommended not to change the vaccine component of influenza A(H1N1)pdm09 for the 2016‐2017 northern hemisphere season but a vaccine strain from subclade 6B.1 (A/Michigan/45/2015) was recommended for use in the 2017‐2018 northern hemisphere influenza season . The observed sustained circulation of influenza A(H1N1)pdm09 viruses with no significant antigenic changes in HA has been suggested to be caused by other genetic changes in internal gene segments increasing the transmissibility and virulence of the virus …”

Regional Diversification of Influenza Activity in Poland During the 2015/16 Epidemic Season

“…A decline in the number of confirmed cases of influenza virus subtype A/H3N2/, which accounted for only 1% in the Kuyavian-Pomerianian and Masovian provinces, was observed in 2015/16 compared with that in 2014/15 (Bednarska et al 2015); a situation similar to that also noted in Russia where this subtype caused only sporadic infections (Kimissarov et al 2016). In contrast, predominance of influenza virus type B was observed the West Pomerania that lies west of the provinces above mentioned near Germany where type B virus was found to predominate in the 2015/16 influenza season (Flu News Europe 2016).…”

“…The present virological data indicate the predominance of infection with influenza virus type A in the eastern Polish provinces: Subcarpathian (91%), Lublin (80%), and Podlaskie (74%), lying near the border with Russia. These infection may be related to border trafficking between the two countries as type A virus was confirmed as predominant from week 3 of 2016 in Russia (Kimissarov et al 2016). However, predominance of type A virus in 2015/16 was also confirmed in Slovakia, Ukraine, Belarus, and Lithuania (Flu News Europe 2016).…”