BACKGROUND Children and adolescents are susceptible to influenza. Vaccination is the most important strategy for preventing influenza, yet there are few studies on the immunogenicity and safety of quadrivalent inactivated influenza vaccine (QIV) containing two A strains (H1N1 and H3N2) and two B lineages (Victoria and Yamagata). Therefore, to further clarify the immunogenicity and safety of QIV in children and adolescents, a meta-analysis was performed to provide a reference for the development of influenza prevention strategies. METHODS PubMed, EMBASE and Cochrane Library were searched for articles published as of February 12, 2019. Random clinical trials comparing the immunogenicity and safety of QIV and TIV among children and adolescents were selected. The main outcomes were comparisons of immunogenicity (seroprotection rate [SPR] and seroconversion rate [SCR] and adverse events using risk ratios (RRs). The meta-analysis was performed using random-effects models. RESULTS Among the 6 months up to 3 years group, QIV showed a higher SPR for B lineages than for TIV-B/Yamagata, with pooled RRs of 3.07 (95% CI: 2.58-3.66) and 1.06 (95% CI: 1.01-1.11), respectively. For the 3 years through 18 years, QIV had a higher SCR and SPR for the Yamagata lineage than for TIV-B/Victoria, with pooled RRs of 2.30 (95% CI: 1.83-2.88) and 1.16 (95% CI: 1.03-1.30), respectively. Compared to TIV-B/Yamagata, a higher SCR and SPR for the Victoria lineage was found for QIV, with RRs of 3.09 (95% CI: 1.99-4.78) and 1.72 (95% CI: 1.22-2.41), respectively. Regarding adverse events, only pain was more frequently reported for QIV than TIV ; the RR was 1.09 (95% CI: 1.02-1.17). CONCLUSIONS The immunogenicity of QIV for common ingredients was similar to that of TIV, but the former exhibited significantly higher immunogenicity for the unique lineage. QIV also had the same reliable safety as TIV.

中文翻译：

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四价和四价流感疫苗在儿童和青少年中的免疫原性和安全性比较。

背景技术儿童和青少年易患流感。接种疫苗是预防流感的最重要策略，但是，关于含有两种A株（H1N1和H3N2）和两种B谱系（维多利亚和山形）的四价灭活流感疫苗（QIV）的免疫原性和安全性的研究很少。因此，为进一步阐明QIV在儿童和青少年中的免疫原性和安全性，进行了荟萃分析，为制定流感预防策略提供了参考。方法检索PubMed，EMBASE和Cochrane图书馆截至2019年2月12日发表的文章。选择比较QIV和TIV在儿童和青少年中的免疫原性和安全性的随机临床试验。与TIV相比，QIV仅报道疼痛更多; RR为1.09（95％CI：1.02-1.17）。结论QIV对常见成分的免疫原性与TIV相似，但前者对独特谱系表现出明显更高的免疫原性。QIV还具有与TIV相同的可靠安全性。