Epidemic characteristics and hemagglutinin gene variation of influenza A(H3N2) in Beijing, 2022—2023
10.3760/cma.j.cn112866-20230713-00076
- VernacularTitle:北京市2022—2023年甲型H3N2流感病毒流行特征与血凝素基因变异分析
- Author:
Jiachen ZHAO
1
;
Yimeng LIU
;
Xiaomin PENG
;
Guilan LU
;
Shujuan CUI
;
Ying SUN
;
Daitao ZHANG
;
Weixian SHI
Author Information
1. 北京市疾病预防控制中心传染病地方病控制所，北京 100013
- Keywords:
Influenza A H3N2 virus;
Genetic characterization;
Evolutionary analysis;
Antigen variation
- From:
Chinese Journal of Experimental and Clinical Virology
2023;37(6):606-612
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To characterize the epidemic of influenza in Beijing from 2022 to 2023 and the variation of gene and antigenicity of hemagglutinin (HA) of influenza A H3N2 virus, so as to provide scientific basis for influenza prevention and control in Beijing.Methods:Statistical analysis was carried out on the result of influenza pathogenic monitoring in Beijing from week 14, 2022 to week 20, 2023, and 79 strains of influenza A H3N2 virus were selected at different time and population sources, and their genetic variation and evolution characteristics were analyzed through HA gene amplification sequencing and antigenicity analysis.Results:From week 14, 2022 to week 20, 2023, 24 244 throat swabs of influenza like cases were collected in Beijing, and 4 987 influenza virus nucleic acid positive cases were detected, including 2 749 influenza A H3N2 positive cases, with a detection rate of 11.34%. Among the 79 strains, 50 strains (63.29%) showed low response, 94.44% of the strains from August to November 2022 had low response, and 54.10% of the strains from February to March 2023 had low response, with a statistically significant difference ( χ2=8.079, P=0.004). Compared with the vaccine strain A/Darwin/9/2021, the HA gene sequence of 79 strains of influenza A H3N2 showed nucleotide similarity of 97.47% to 98.47% and amino acid similarity of 97.05% to 98.17%. Genetic evolution analysis showed that the 18 strains isolated from August to November 2022 were all distributed in the 3C.2a1b.2a.1a.1 branch, while the 61 strains isolated from February to March 2023 all belonged to the 3C.2a1b.2a.3a.1 branch. Compared with the vaccine strain, there were multiple site mutations distributed at multiple antigenic determinants and receptor binding sites in A, B, C, D, and E. All strains had potential glycosylation sites of 8NST, 22NGT, 38NAT, 45NSS, 63NCT, 126NWT, 133NGT, 246NST, 285NGS, 483NET, while one strain missed 165NVT glycosylation sites; 55 strains between February and March 2023 missed 122NES glycosylation sites. Conclusions:The HA gene locus of influenza A H3N2 virus detected in Beijing from week 14, 2022 to week 20, 2023 showed multiple mutations, continuous monitoring of this subtype variation is crucial.
