He Fang, Yu Huiyan, Liu Liqi, Li Xiyan, Xing Yadong, Yang Lei, Yang Pengfei, Zhu Liguo, Li Zi
Huai'an Center for Disease Control and Prevention, Huai'an 223299, China.
Department of Acute Infectious Disease Control and Prevention, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing 210008, China.
Biosaf Health. 2024 Nov 20;6(6):319-326. doi: 10.1016/j.bsheal.2024.11.007. eCollection 2024 Dec.
Pigs are vital genetic mixing vessels for human and avian influenza viruses because their tracheal epitheliums possess both sialic acid α-2,6-Gal and α-2,3-Gal receptors. Cross-species transmission of influenza A viruses from swine to humans occurs occasionally. The first case of human infection with the Eurasian avian-like H1N1 swine influenza virus (EAH1N1 SIVs) genotype G4 was detected in Jiangsu Province, China, in February 2023, and backtracking epidemiological investigations did not reveal a clear source of the infection. The hemagglutination (HA) and neuraminidase (NA) amino acid variant sites, antiviral drug susceptibility, and antigenic variation of the isolated A/Jiangsu/27271/2023 (JS/27271/23) virus were analyzed, and we evaluated the protective effect of sera collected from occupationally exposed populations in 2024 against the virus. Compared with the vaccine strain, the nucleotide sequence similarities of JS/27271/23 HA and NA were 96.5 % and 95.2 %, respectively. JS/27271/23 was sensitive to polymerase inhibitors (favipiravir and baloxavir), and the antigenicity of its HA protein was 8-fold different from that of the vaccine strain. The percentage of occupationally exposed population with antibody titers of ≥ 40 against A/Hunan/42443/2015 (HN/42443/15) and A/Jiangsu/1/2011 (JS/1/11) were 7.25 % and 2.25 %, respectively, and the geometric mean titers (GMT) were 6.24 and 5.34, respectively. Out of 400 serum samples examined, none had antibody titers of ≥ 40 against JS/27271/23. This suggests that low serum levels of antibodies to EAH1N1 SIVs in occupationally exposed populations may not provide adequate protection because of significant differences in amino acid sites and antigenicity between this virus and the current vaccine strain of EAH1N1 SIVs. There is no evidence of human-to-human transmission of EAH1N1 SIVs. Therefore, surveillance for EAH1N1 SIVs and the development of new vaccine strains are required.
猪是人流感病毒和禽流感病毒重要的基因混合载体，因为它们的气管上皮同时拥有唾液酸α-2,6-半乳糖和α-2,3-半乳糖受体。甲型流感病毒偶尔会从猪跨物种传播给人类。2023年2月，中国江苏省检测到首例人类感染欧亚禽源类H1N1猪流感病毒（EAH1N1 SIVs）G4基因型病例，溯源性流行病学调查未发现明确感染源。对分离出的A/江苏/27271/2023（JS/27271/23）病毒的血凝素（HA）和神经氨酸酶（NA）氨基酸变异位点、抗病毒药物敏感性及抗原变异情况进行了分析，并评估了2024年职业暴露人群血清对该病毒的保护效果。与疫苗株相比，JS/27271/23的HA和NA核苷酸序列相似性分别为96.5%和95.2%。JS/27271/23对聚合酶抑制剂（法匹拉韦和巴洛沙韦）敏感，其HA蛋白的抗原性与疫苗株相差8倍。职业暴露人群中抗A/湖南/42443/2015（HN/42443/15）和抗A/江苏/1/2011（JS/1/11）抗体效价≥40的比例分别为7.25%和2.25%，几何平均滴度（GMT）分别为6.24和5.
