2016 - 2019年包头市甲型H1N1流感病毒基因分析

目的 了解包头市流感病毒的变异情况，评估流行株在致病性、毒性、耐药性方面的改变，以研究结果为依据，为流感防控、指导抗流感药物的选用及筛选新的疫苗代表株提供依据。方法 按分离比例随机抽取2016 - 2019年甲型H1N1疫苗株进行基因测序分析。结果 包头市2016 - 2019的甲型H1N1分离株主要属于6B.1A分支，与疫苗株A/Brisbane/02/2018同源性较高。各年度病毒株与疫苗株A/Brisbane/02/2018的组间遗传距离分别为0.014，0.016，0.014和0.012。分离株抗原位点集中在 Sa 区的163 - 164位点发生变异。分离株2018 - 1139 - HA.seq发生了H275Y位点变异。结论 包头市2016 - 2018年度内甲型H1N1流感病毒分离株与A/Brisbane/02/2018亚型流感病毒同源性较高。相对A/Brisbane/02/2018疫苗株而言，本次分析的病毒基因并未发生抗原漂移现象，可以初步判定目前推荐的疫苗株对当前流行的甲型H1N1流感具有较好的保护效果。

Genetic analysis of influenza A (H1N1) virus in Baotou, 2016-2019

To analyze the surveillance results and epidemic situation of influenza in Hainan Province during2016-2020 surveillance season, and to provide scientific evidence for the prevention of influenza. Methods The influenzalike illness (ILI) monitoring data and pathogen surveillance results from “China’s Influenza Surveillance Information System”in Hainan Province during 2016-2020 season were collected and statistically analyzed. Results 157361 cases of ILI werereported by the 6 sentinel hospitals in Hainan province during 2016-2020 season, and the total percentage of influenza likeillness (ILI%) was 3.05%. The majority of ILI cases were reported from the 0-5 age group, accounting for 51.01%. A total of25231 cases ILI specimens were detected by the 5 influenza surveillance network laboratories in Hainan province, and thetotal positive rate was 14.67%. The influenza activity appeared both summer peak and winter-spring peak in the 2017-2018and 2019-2020 season, concentrating in April-September with supreme peak 53.64% and November-Next year March with42.14% . The 2016 -2017 and 2018 -2019 season presented only winter -spring peak concentrating in October -next yearMarch with supreme peak 54.14%, while showing no obvious summer peak. The influenza predominant viruses throughout thefour-surveillance season underwent the alternation of H1N1, H3N2 and type B. Conclusion The influenza epidemic situationwas stable during 2016-2020 season and different predominant viruses’ types underwent the alternation of A (H1N1) pdm09,H3N2, Victoria and Yamagata. We should continue to pay more attention to influenza virus alternation and strengthen thesurveillance analysis of influenza virus.