Background: During the coronavirus disease 2019(COVID-19)pandemic,seasonal influenza activity declined globally and remained below previous seasonal levels,but intensified in China since 2021.Preventive measures to CO...Background: During the coronavirus disease 2019(COVID-19)pandemic,seasonal influenza activity declined globally and remained below previous seasonal levels,but intensified in China since 2021.Preventive measures to COVID-19 accompanied by different epidemic characteristics of influenza in different regions of the world.To better respond to influenza outbreaks under the COVID-19 pandemic,we analyzed the epidemiology,antigenic and genetic characteristics,and antiviral susceptibility of influenza viruses in the mainland of China during 2020–2021.Methods: Respiratory specimens from influenza like illness cases were collected by sentinel hospitals and sent to network laboratories in Chinese National Influenza Surveillance Network.Antigenic mutation analysis of influenza virus isolates was performed by hemagglutination inhibition assay.Next-generation sequencing was used for genetic analyses.We also conducted molecular characterization and phylogenetic analysis of circulating influenza viruses.Viruses were tested for resistance to antiviral medications using phenotypic and/or sequence-based methods.Results: In the mainland of China,influenza activity recovered in 2021 compared with that in 2020 and intensified during the traditional influenza winter season,but it did not exceed the peak in previous years.Almost all viruses isolated during the study period were of the B/Victoria lineage and were characterized by genetic diversity,with the subgroup 1A.3a.2 viruses currently predominated.37.8%viruses tested were antigenically similar to reference viruses representing the components of the vaccine for the 2020–2021 and 2021–2022 Northern Hemisphere influenza seasons.In addition,China has a unique subgroup of 1A.3a.1 viruses.All viruses tested were sensitive to neuraminidase inhibitors and endonuclease inhibitors,except two B/Victoria lineage viruses identified to have reduced sensitivity to neuraminidase inhibitors.Conclusions: Influenza activity increased in the mainland of China in 2021,and caused flu season in the展开更多
目的了解乙型流感Victoria株系(influenza B victoria lineage,Bv)疫情的分子基础,分析该株系流感的流行趋势。方法基于广东流感监测网络(GDISN)采用时空分布方法筛选流感Bv毒株,检测HA/NA基因核苷酸序列;采用MEGA 7.026、Datamonkey 2....目的了解乙型流感Victoria株系(influenza B victoria lineage,Bv)疫情的分子基础,分析该株系流感的流行趋势。方法基于广东流感监测网络(GDISN)采用时空分布方法筛选流感Bv毒株,检测HA/NA基因核苷酸序列;采用MEGA 7.026、Datamonkey 2.0、NetNGlyc 1.0 Server、SPSS 23.0软件等,分析其核苷酸/氨基酸序列的同源性、进化树、氨基酸与表位变异、糖基化位点和进化选择性等。结果广东2021年毒株较2020年毒株同源性呈现明显差异(P<0.01),2021年下半年毒株(17株)HA基因与疫苗株B/Austria/1359417/2021同源性高达(99.28±0.25)%。HA基因A表位(HN/Q、AT和RG)、B表位(PL和NK)和D表位(SN/D和TA)以及RBS位点(PQ)发生变异;2020年毒株呈Bv.1a.3株系特征,2021年毒株主要呈Bv.1a.3a.2株系特征。HA与NA基因潜在糖基化位点均无有意义改变;NA基因没有出现药敏位点变异;HA和NA基因氨基酸负向选择位点分别是73、138、437和497位点和179、321和335位点。结论广东2021年毒株HA和NA基因较2020年毒株均发生较明显变异,尤以2021年下半年毒株的HA基因变异明显;Bv毒株HA基因表位出现新变异,提示引发下一流感季节广泛局部流行的预警。展开更多
文摘Background: During the coronavirus disease 2019(COVID-19)pandemic,seasonal influenza activity declined globally and remained below previous seasonal levels,but intensified in China since 2021.Preventive measures to COVID-19 accompanied by different epidemic characteristics of influenza in different regions of the world.To better respond to influenza outbreaks under the COVID-19 pandemic,we analyzed the epidemiology,antigenic and genetic characteristics,and antiviral susceptibility of influenza viruses in the mainland of China during 2020–2021.Methods: Respiratory specimens from influenza like illness cases were collected by sentinel hospitals and sent to network laboratories in Chinese National Influenza Surveillance Network.Antigenic mutation analysis of influenza virus isolates was performed by hemagglutination inhibition assay.Next-generation sequencing was used for genetic analyses.We also conducted molecular characterization and phylogenetic analysis of circulating influenza viruses.Viruses were tested for resistance to antiviral medications using phenotypic and/or sequence-based methods.Results: In the mainland of China,influenza activity recovered in 2021 compared with that in 2020 and intensified during the traditional influenza winter season,but it did not exceed the peak in previous years.Almost all viruses isolated during the study period were of the B/Victoria lineage and were characterized by genetic diversity,with the subgroup 1A.3a.2 viruses currently predominated.37.8%viruses tested were antigenically similar to reference viruses representing the components of the vaccine for the 2020–2021 and 2021–2022 Northern Hemisphere influenza seasons.In addition,China has a unique subgroup of 1A.3a.1 viruses.All viruses tested were sensitive to neuraminidase inhibitors and endonuclease inhibitors,except two B/Victoria lineage viruses identified to have reduced sensitivity to neuraminidase inhibitors.Conclusions: Influenza activity increased in the mainland of China in 2021,and caused flu season in the
文摘目的了解乙型流感Victoria株系(influenza B victoria lineage,Bv)疫情的分子基础,分析该株系流感的流行趋势。方法基于广东流感监测网络(GDISN)采用时空分布方法筛选流感Bv毒株,检测HA/NA基因核苷酸序列;采用MEGA 7.026、Datamonkey 2.0、NetNGlyc 1.0 Server、SPSS 23.0软件等,分析其核苷酸/氨基酸序列的同源性、进化树、氨基酸与表位变异、糖基化位点和进化选择性等。结果广东2021年毒株较2020年毒株同源性呈现明显差异(P<0.01),2021年下半年毒株(17株)HA基因与疫苗株B/Austria/1359417/2021同源性高达(99.28±0.25)%。HA基因A表位(HN/Q、AT和RG)、B表位(PL和NK)和D表位(SN/D和TA)以及RBS位点(PQ)发生变异;2020年毒株呈Bv.1a.3株系特征,2021年毒株主要呈Bv.1a.3a.2株系特征。HA与NA基因潜在糖基化位点均无有意义改变;NA基因没有出现药敏位点变异;HA和NA基因氨基酸负向选择位点分别是73、138、437和497位点和179、321和335位点。结论广东2021年毒株HA和NA基因较2020年毒株均发生较明显变异,尤以2021年下半年毒株的HA基因变异明显;Bv毒株HA基因表位出现新变异,提示引发下一流感季节广泛局部流行的预警。
