【摘要】 目的 了解2021年—2022年宁夏Victoria系乙型流感病毒基因变异情况，为宁夏流感防控提供参考依据。方法 采集流感样病例标本进行核酸检测和病毒分离，对30株Victoria系乙型流感毒株的HA和NA片段进行基因测序，利用生物信息学软件分析进化变异特征。结果 30株宁夏Victoria系乙型流感毒株HA和NA基因在进化上与疫苗株B/Washington/02/2019(2020—2022)亲缘关系较近，属于V1A.3分支。HA基因的核苷酸和氨基酸同源性分别为98.5%～99.0%和98.0%～98.6%;NA基因的核苷酸和氨基酸同源性分别为99.0%～99.4%和98.9%～99.6%。与疫苗株B/Washington/02/2019相比，多数毒株在HA区有H122Q、A127T、R133G、G141R、P144L、N150K、G184E、N197D、K203R和R279K突变，涉及3个抗原表位，并在受体结合位点140-loop、190-helix及240-loop处存在突变位点。所有毒株均未发生耐药位点变异。结论 2021年—2022年宁夏Victoria系乙型流感病毒与本年度疫苗株亲缘关系较近，但其HA蛋白的重要氨基酸位点发生多处变异，可能导致流感病毒发生抗原性漂移，减弱疫苗的保护作用。更多还原

【Abstract】 Objective This paper aims to analyze the genetic variation of hemagglutinin(HA) and neuraminidase(NA) of influenza B/Victoria lineage virus(B/Vic) from 2021 to 2022 in Ningxia, so as to provide reference for prevention and control of influenza virus. Methods The throat swab samples of influenza like illness(ILI) were collected for nucleic acids and virus isolation testing. HA and NA fragments of 30 Victoria influenza B strains were sequenced and the evolutionary variation characteristics were analyzed by bioinformatics software. Results HA and NA genes of 30 B/Vic isolated strains were closely related to the vaccine strain B/Washington/02/2019(2020—2022), belonging to the V1A.3 branch. The nucleotide and amino acid similarity of HA or NA gene ranged from 98.5% to 99.0% and 98.0% to 98.6%, or 99.0% to 99.4% and 98.9% to 99.6%, respectively. Compared with the vaccine strain B/Washington/02/2019, most of the B/Vic isolates had amino acid variations of HA gene at the sites of H122Q, A127T, R133G, G141R, P144L, N150K, G184E, N197D, K203R and R279K, involving three epitopes, and mutation sites were found at the receptor binding sites of 140-loop, 190-helix and 240-loop. No mutation was found on the neuraminidase inhibitor resistance sites and NA enzyme activity sites. Conclusion The influenza B/Victoria lineage virus from 2021 to 2022 in Ningxia are closely related to the WHO recommended vaccine strain. However, the accumulation of amino acid mutations in HA gene may lead to antigenic drift of influenza B virus, which may weaken the protective effect of vaccine.更多还原