Leslie Dan School of Pharmacy, University of Toronto, Toronto, ON, Canada; Sanofi Pasteur, Toronto, ON, Canada.
Leslie Dan School of Pharmacy, University of Toronto, Toronto, ON, Canada; Sanofi Pasteur, Toronto, ON, Canada.
Vaccine. 2021 Mar 15;39 Suppl 1:A24-A35. doi: 10.1016/j.vaccine.2020.09.004. Epub 2021 Jan 7.
Influenza vaccine efficacy/effectiveness can vary from season to season due in part to the dominant circulating strains and antigenic matching. This study reviews the relative vaccine efficacy/effectiveness (rVE) of high-dose inactivated trivalent influenza vaccine (HD-IIV3) compared to standard-dose influenza vaccines (SD-IIV) in adults aged ≥ 65 years against influenza-associated outcomes. Additional sub-analyses of HD-IIV3 rVE were performed by the predominantly circulating influenza strain and the antigenic match or mismatch of the vaccine against the predominant circulating strains.
An updated systematic review and meta-analysis was conducted for studies assessing the rVE of HD-IIV3 against probable/laboratory-confirmed influenza-like illness (ILI), hospital admissions, and death in adults aged ≥ 65 years. Results from individual seasons were extracted from the studies, and viral surveillance data were used to determine the dominant circulating strains and antigenic match for each season. Results were then stratified based on clinical outcomes and seasonal characteristics and meta-analyzed to estimate pooled rVEs of HD-IIV3.
15 publications were meta-analyzed after screening 1,293 studies, providing data on 10 consecutive influenza seasons and over 22 million individuals receiving HD-IIV3 in randomized and observational settings. Across all influenza seasons, HD-IIV3 demonstrated improved protection against ILI compared to SD-IIV (rVE = 15.9%, 95% CI: 4.1-26.3%). HD-IIV3 was also more effective at preventing hospital admissions from all-causes (rVE = 8.4%, 95% CI: 5.7-11.0%), as well as influenza (rVE = 11.7%, 95% CI: 7.0-16.1%), pneumonia (rVE = 27.3%, 95% CI: 15.3-37.6%), combined pneumonia/influenza (rVE = 13.4%, 95% CI: 7.3-19.2%) and cardiorespiratory events (rVE = 17.9%, 95% CI: 15.0-20.8%). Reductions in mortality due to pneumonia/influenza (rVE = 39.9%, 95% CI: 18.6-55.6%) and cardiorespiratory causes (rVE = 27.7%, 95% CI: 13.2-32.0%) were also observed. Similar pooled rVEs were observed in both matched and mismatched seasons and in seasons where A/H3N2 or A/H1N1 strains were predominantly circulating.
Evidence over 10 consecutive influenza seasons and in more than 34 million individuals aged ≥ 65 years suggests that HD-IIV3 is consistently more effective than SD-IIV at reducing influenza cases as well as influenza-associated clinical complications irrespective of circulating strain and antigenic match. A video summary of the article can be accessed via the Supplementary data link at the end of this article.
流感疫苗的效果/效力可能因季节而异，部分原因是主要流行株和抗原匹配情况的不同。本研究综述了高剂量灭活三价流感疫苗（HD-IIV3）与标准剂量流感疫苗（SD-IIV）在≥65 岁老年人中针对流感相关结局的相对疫苗效果/效力（rVE）。还根据主要流行株和疫苗对主要流行株的抗原匹配或不匹配情况，对 HD-IIV3 的 rVE 进行了额外的亚组分析。
对评估 HD-IIV3 对≥65 岁成年人中可能/实验室确诊的流感样疾病（ILI）、住院和死亡的 rVE 的研究进行了更新的系统评价和荟萃分析。从研究中提取了各个季节的结果，使用病毒监测数据确定了每个季节的主要流行株和抗原匹配情况。然后根据临床结局和季节性特征对结果进行分层，并进行荟萃分析以估计 HD-IIV3 的汇总 rVE。
在筛选了 1293 项研究后，有 15 篇文献进行了荟萃分析，提供了 10 个连续流感季节的数据，超过 2200 万人在随机和观察性环境中接受了 HD-IIV3 治疗。在所有流感季节中，与 SD-IIV 相比，HD-IIV3 对 ILI 的预防效果更好（rVE=15.9%，95%CI：4.1-26.3%）。HD-IIV3 还能更有效地预防因所有原因导致的住院（rVE=8.4%，95%CI：5.7-11.0%）、流感（rVE=11.7%，95%CI：7.0-16.1%）、肺炎（rVE=27.3%，95%CI：15.3-37.6%）、肺炎和流感合并（rVE=13.4%，95%CI：7.3-19.2%）和心肺事件（rVE=17.9%，95%CI：15.0-20.8%）。还观察到因肺炎和流感（rVE=39.9%，95%CI：18.6-55.6%）和心肺原因（rVE=27.7%，95%CI：13.2-32.0%）导致的死亡率降低。在匹配和不匹配季节以及 A/H3N2 或 A/H1N1 株占主导地位的季节中，也观察到了相似的汇总 rVE。
在 10 个连续的流感季节和超过 3400 万≥65 岁的人群中，证据表明，HD-IIV3 始终比 SD-IIV 更有效，可降低流感病例以及流感相关临床并发症的发生，无论流行株和抗原匹配情况如何。本文的视频摘要可通过文末的补充数据链接获取。
