Evolution and genetic variation of HA and NA genes of H1N1 influenza virus in Shanghai， 2024
10.19428/j.cnki.sjpm.2025.250123
- VernacularTitle:2024年上海地区H1N1流感病毒HA与NA基因的进化与变异
- Author:
Lufang JIANG
1
;
Wei CHU
2
;
Xuefei QIAO
3
;
Pan SUN
4
;
Senmiao DENG
4
;
Yuxi WANG
1
;
Xue ZHAO
5
;
Jiasheng XIONG
6
;
Xihong LYU
3
;
Linjuan DONG
7
;
Yaxu ZHENG
8
;
Yinzi CHEN
8
;
Chenyan JIANG
6
;
Chenglong XIONG
1
;
Jian CHEN
8
Author Information
1. School of Public Health, Key Laboratory of Public Health Safety, Ministry of Education, Fudan University, Shanghai 200032, China
2. Huangpu District Center for Disease Control and Prevention(Huangpu District Health Supervision Institute), Shanghai 200023, China
3. Songjiang District Center for Disease Control and Prevention(Songjiang District Health Supervision Institute), Shanghai 201620, China
4. Jiading District Center for Disease Control and Prevention(Jiading District Health Supervision Institute), Shanghai 201899, China
5. Institute of Microbiology Laboratory, Shanghai Municipal Center for Disease Control and Prevention, Shanghai 201107, China
6. Division of Emergency Management, Shanghai Municipal Center for Disease Control and Prevention, Shanghai 201107, China
7. Minhang District Center for Disease Control and Prevention(Minhang District Health Supervision Institute), Shanghai 201101, China
8. Institute of Infections Disease Control and Prevention, Shanghai Municipal Center for Disease Control and Prevention, Shanghai 201107, China
- Publication Type:Journal Article
- Keywords:
influenza virus;
HA gene;
NA gene;
amino acid;
variation;
evolution
- From:
Shanghai Journal of Preventive Medicine
2025;37(9):719-724
- CountryChina
- Language:Chinese
-
Abstract:
ObjectiveTo analyze the evolutionary characteristics and genetic variations of the HA (hemagglutinin) and NA (neuraminidase) genes of influenza A(H1N1) viruses in Shanghai during 2024, to investigate their transmission patterns, and to evaluate their potential impact on vaccine effectiveness. MethodsFrom January to October 2024, throat swab specimens were collected from influenza like illness (ILI) patients at 4 hospitals in Shanghai. Real-time fluorescence ploymerase chain reaction (RT-PCR) was used for virus detection and isolation of H1N1 influenza viruses. Forty influenza A(H1N1) virus strains were sequenced using Illumina NovaSeq 6000 platform, followed by phylogenetic analyses, genetic distance analysis, and amino acid variation analyses of HA and NA genes. ResultsPhylogenetic tree of the HA and NA genes revealed that the 40 influenza A(H1N1) virus strains circulating in Shanghai in 2024 exhibited no significant geographic clustering, with a broad origin of strains and complex transmission chains. Genetic distance analyses demonstrated that the average intra-group genetic distances of HA and NA genes among the Shanghai strains were 0.005 1±0.000 6 and 0.004 6±0.000 6, respectively, which were comparable to or higher than those observed in global surveillance strains. Both HA and NA genes displayed frequent mutations. Compared to the 2023‒2024 and 2024‒2025 Northern Hemisphere A(H1N1) vaccine strains (WHO-recommended), the HA proteins of 40 Shanghai strains exhibited amino acid substitutions at positions 120, 137, 142, 169, 216, 223, 260, 277, 356 and 451, with critical mutations at positions 137 and 142 located within the Ca2 antigenic determinant. Furthermore, mutations in the NA protein were observed at positions 13, 50, 200, 257, 264, 339 and 382. ConclusionThe genetic background of the 2024 Shanghai influenza A(H1N1) virus strains is complex and diverse, and antigenic variation may affect vaccine effectiveness. Therefore, it is recommended to enhance genomic surveillance of influenza viruses, evaluate vaccine suitability, and implement more targeted prevention and control strategies against imported influenza viruses.
