Xie Hang, Xiang Ruoxuan, Wan Hamilton J, Plant Ewan P, Radvak Peter, Kosikova Martina, Li Xing, Zoueva Olga, Ye Zhiping, Wan Xiu-Feng
Laboratory of Respiratory Viral Diseases, Division of Viral Products, Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, USA.
Division of Biostatistics, Office of Biostatistics and Epidemiology, Center for Biologics Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, USA.
Clin Infect Dis. 2021 Jun 1;72(11):e776-e783. doi: 10.1093/cid/ciaa1481.
The influenza activity of the 2019/20 season remained high and widespread in the United States with type B viruses predominating the early season. The majority of B viruses characterized belonged to B/Victoria (B/Vic) lineage and contained a triple deletion of amino acid (aa) 162-164 in hemagglutinin (3DEL). These 3DEL viruses are antigenically distinct from B/Colorado/06/2017 (CO/06)-the B/Vic vaccine component of the 2018/19 and 2019/20 seasons representing the viruses with a double deletion of aa 162-163 in hemagglutinin (2DEL).
We performed molecular characterization and phylogenetic analysis of circulating B/Vic viruses. We also conducted hemagglutination inhibition (HAI) assay using archived human postvaccination sera collected from healthy subjects administered with different types of 2018/19 or 2019/20 seasonal vaccines. Their HAI cross-reactivity to representative 3DEL viruses was analyzed.
The CO/06-specific human postvaccination sera, after being adjusted for vaccine type, had significantly reduced HAI cross-reactivity toward representative 3DEL viruses, especially the 136E+150K subgroup. The geometric mean titers against 3DEL viruses containing 136E+150K mutations were 1.6-fold lower in all populations (P = .051) and 1.9-fold lower in adults (P = .016) compared with those against the 136E+150N viruses.
Our results indicate that postvaccination antibodies induced by the B/Vic vaccine component of the 2019/20 influenza season had reduced HAI cross-reactivity toward predominant 3DEL viruses in the United States. A close monitoring of the 3DEL 136E+150K subgroup is warranted should this subgroup return and predominate the 2020/21 influenza season.
2019/20流感季，美国流感活动持续高发且广泛传播，B型病毒在季初占主导。大多数经特征鉴定的B型病毒属于B/维多利亚（B/Vic）谱系，其血凝素（HA）中存在162 - 164位氨基酸的三重缺失（3DEL）。这些3DEL病毒在抗原性上与B/科罗拉多/06/2017（CO/06）不同，CO/06是2018/19和2019/20流感季的B/Vic疫苗成分，代表血凝素中存在162 - 163位氨基酸双重缺失（2DEL）的病毒。
我们对流行的B/Vic病毒进行了分子特征分析和系统发育分析。我们还使用从接种不同类型2018/19或2019/20季节性疫苗的健康受试者中收集的存档人接种后血清进行了血凝抑制（HAI）试验。分析了它们对代表性3DEL病毒的HAI交叉反应性。
针对CO/06的人接种后血清，在根据疫苗类型进行调整后，对代表性3DEL病毒的HAI交叉反应性显著降低，尤其是对136E + 150K亚组。与针对136E + 150N病毒相比，所有人群中针对含有136E + 150K突变的3DEL病毒的几何平均滴度低1.6倍（P = 0.051），成人中低1.9倍（P = 0.016）。
我们的结果表明，2019/20流感季B/Vic疫苗成分诱导的接种后抗体对美国主要的3DEL病毒的HAI交叉反应性降低。如果该136E + 150K亚组在2020/21流感季再次出现并占主导，有必要对其进行密切监测。
