Hemagglutinin genetic characteristics of the influenza B virus Victoria lineage in Fujian Province from 2015 to 2022，China

Abstract Objective This study analyzed the molecular characteristics of hemagglutinin(HA) of the influenza B virus (IBV) Victoria lineage in Fujian Province from 2015 to 2022.Methods Fujian flu surveillence data during 2015.1.1-2022.3.31 were collected through China’s Disease Prevention and Control Information System and counted.The strains were obtained from canine kidney passaged cells or chicken embryo culture isolates of influenza-like cases from the 2015–2022 Influenza Network Surveillance System.The virus nucleic acid was extracted, and the HA gene fragment was amplified by RT-PCR and sequenced .MEGA5.0, Net NGlyc 1.0 Server software to analyse genetic characteristics.Results From 2015 to 2022, the HA gene of the influenza B virus Victoria lineage in Fujian Province had three nucleotide lengths, 1758 bp、1752 bp and 1749 bp respectively.The HA gene differential loci are mainly involved in the antigenic determinant clusters 120-loop, 150-loop, 160-loop, 190-helix and several receptor binding sites(RBS).145, 166 and 197 glycosylation sites are more diverse relative to other glycosylation sites.Conclusion The variation of the HA gene of influenza B virus Victoria lineage in Fujian Province from 2015 to 2022 is diversifying and the number of variant loci is increasing year by year, and research should continue to be strengthened to provide basic data for the prevention and control of the epidemic in Fujian Province.