1Institute of Health, Kunming Medical University, Kunming, 650031 China.
Huai'an Center for Disease Control and Prevention, Huai'an, 223005 China.
Antimicrob Resist Infect Control. 2019 Oct 28;8:164. doi: 10.1186/s13756-019-0631-2. eCollection 2019.
Annual influenza vaccination is the most effective way to prevent influenza. Influenza vaccines have traditionally included the hemagglutinins (HA) and neuraminidases (NA) from the two A viruses (H1N1 and H3N2) and either B Yamagata or B Victoria. Mismatches between circulating isolates of influenza B and the vaccines are very common. Taking 2017/2018 winter in northern hemisphere as an example, this study was designed to find out the reasons for mismatch between the trivalent influenza vaccine (TIV) and most of the epidemic isolates at that time, and to discuss if there are some optimized programs for seasonal influenza vaccines.
HA and NA sequences of the seasonal isolates circulating from December 1, 2017 to February 28, 2018, and in the previously other 7 winters in northern hemisphere from Global Initiative on Sharing All Influenza Data (GISAID) and the influenza database of National Center for Biotechnology Information (NCBI). Phylogenetic trees and genetic distances were constructed or calculated by using MAFFT and MEGA 6.0 software.
Influenza B composition in the TIV recommendation mismatched most of circulating viruses in 2017/2018 winter; the vaccine strain was from the B/Victoria lineage, while most of epidemic isolates were from the B/Yamagata lineage. The epidemic lineage of influenza B reached its peak a little late in the previous winter might be responsible for this mismatch. During 2010-2018, the mean genetic distances between epidemic isolates of influenza A (H1N1 and H3N2) and the vaccines were no higher than 0.02375 ± 0.00341 in both HA and NA. However, concerning influenza B virus, when forecasting done well, the mean genetic distances between epidemic isolates and the vaccines were no higher than 0.02368 ± 0.00272; otherwise, the distances could reach 0.13695 ± 0.00238.
When applying quadrivalent influenza vaccines (QIVs) for vaccination, the recommendations of compositions for influenza B could be altered and assessed once in 3 or 4 years; when economic burden was considered intensively and TIVs were utilized, the recommended compositions for influenza B could be announced in April or May, rather than in February or March as now.
每年接种流感疫苗是预防流感最有效的方法。流感疫苗传统上包含来自两种 A 病毒（H1N1 和 H3N2）的血凝素（HA）和神经氨酸酶（NA），以及 B Yamagata 或 B Victoria。流感 B 型病毒的循环分离株与疫苗之间的不匹配非常常见。以 2017/2018 年冬季的北半球为例，本研究旨在找出三价流感疫苗（TIV）与当时大部分流行分离株不匹配的原因，并讨论是否有一些针对季节性流感疫苗的优化方案。
从 Global Initiative on Sharing All Influenza Data（GISAID）和美国国家生物技术信息中心（NCBI）的流感数据库中，收集 2017 年 12 月 1 日至 2018 年 2 月 28 日期间以及过去 7 个冬季北半球流行的季节性分离株的 HA 和 NA 序列。使用 MAFFT 和 MEGA 6.0 软件构建或计算系统发育树和遗传距离。
2017/2018 年冬季 TIV 推荐的流感 B 成分与大多数流行病毒不匹配；疫苗株来自 B/Victoria 谱系，而大多数流行分离株来自 B/Yamagata 谱系。上一个冬季流感 B 流行谱系达到高峰的时间稍晚，可能是造成这种不匹配的原因。在 2010-2018 年期间，甲型流感（H1N1 和 H3N2）和疫苗之间的流行分离株的平均遗传距离在 HA 和 NA 中均不高于 0.02375±0.00341。然而，对于流感 B 病毒，如果预测做得好，流行分离株与疫苗之间的平均遗传距离不高于 0.02368±0.00272；否则，距离可达 0.13695±0.00238。
在接种四价流感疫苗（QIV）时，可以每 3 或 4 年修改和评估一次流感 B 的成分建议；在考虑到经济负担并使用 TIV 时，可以在 4 月或 5 月而不是现在的 2 月或 3 月宣布流感 B 的推荐成分。
