摘要本研究对2014年4月至2017年8月烟台市两家哨点医院流感样病例采集咽试子标本,分离流感病毒,血凝抑制实验分型并对甲型流感HA基因序列测定,进行系统发生学分析及主要氨基酸位点变异分析,Pepitope模型评估甲型流感疫苗保护效果.结果显示:仅H3N2甲型流感病毒抗原性发生变异;甲型H1N1pdm09流感毒株8株属于6B.2,14株属于6B.1基因亚型,H3N2流感毒12株属于3C.3a基因亚型,33株属于3C.2a基因亚型;甲型流感病毒HA蛋白多个抗原位点、潜在糖基化位点发生变异;2015—2016和2016—2017年监测季甲型H1N1pdm09流感病毒的疫苗保护效果分别为最佳匹配疫苗的77.29%和79.21%;2014—2015、2015—2016和2016—2017年流感监测季甲型H3N2流感病毒的疫苗保护效果分别为最佳匹配疫苗的-5.18%、16.97%和42.05%.表明2014—2017年烟台地区甲型流感病毒持续发生基因变异,H3N2流感疫苗保护性较差而甲型H1N1pdm09流感疫苗具有较好的保护作用.

abstractsIn this study, the swabs were collected among patients with an influenza?like illness (ILI) admitted to 2 sentinel surveillance hospitals of Yantai from April 2014 to August 2017. All specimen were cultured and identified by hemagglutination inhibition assay. Complete sequences of Hemagglutinin (HA) of influenza A were amplified, sequenced and analyzed using molecular and phylogenetic methods. The potential vaccine efficacy were calculated using Pepitope model. The results showed that the antigenicity of A (H3N2) had changed greatly. 8 strains of influenza A (H1N1) pdm09 belonged to subclade 6B.1 and 14 strains clustered in 6B.2. 12 strains of influenza A (H3N2) fell into subgroup 3C.3a and 33 strains clustered in 3C.2a. Several residues at antigen sites and potential glycosylation sites had changed in influenza A strains. Vaccine efficacy of influenza A (H1N1) pdm09 in 2015/2016 and 2016/2017 seasons were 77.29% and 79.11% of that of a perfect match with vaccine strain, meanwhile vaccine efficacy of influenza A (H3N2) in 2014/2015, 2015/2016 and 2016/2017 were-5.18%, 16.97% and 42.05% separately. In conclusion, the influenza A virus circulated in Yantai from 2014 to 2017 presented continual genetic variation. The recommended vaccine strains still afforded protection against influenza A (H1N1) pdm09 strains and provided suboptimal protection against influenza A (H3N2) strains.