Background The high-dose (HD) Fluzone influenza vaccine is currently recommended for individuals 65 and older, since it was shown in past studies to improve antibody responses and vaccine efficacy (VE) compared to a standard-dose (SD) formulation. Since influenza vaccines are frequently reformulated, monitoring any potential changes in VE is crucial. Traditional efficacy trials can be costly and time-consuming. Conducting immunogenicity studies with updated formulations and estimating VE with the resulting data is a more efficient way to assess these vaccines over time. Hemagglutination inhibition (HAI) titers are considered a reliable correlate of protection in influenza vaccine research and have previously been used to estimate VE. Methods We analyzed data from a human vaccine cohort who received either the SD or HD Fluzone split-inactivated influenza vaccine during influenza seasons 2013/14 to 2021/22. We used a previously developed statistical model to map pre- and post-vaccination HAI titers to protection probabilities, and computed differences in vaccine efficacy (VE) of the HD vaccine in older ( 65 years) populations compared to SD vaccines in the same age group and in younger (<65 years) adults. Results We found that for participants aged 65 and older, the HD vaccine generally improved the estimated VE across seasons. However, we also found that HD recipients often had a lower estimated VE than younger SD recipients. Conclusions While HD Fluzone vaccines lead to a small increase in estimated VE compared to SD in older adults, further increases in dose or other developments to improve VE should be considered.

中文翻译：

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根据 HAI 滴度估计标准剂量和高剂量 Fluzone 疫苗对甲型流感的疗效


背景 目前建议 65 岁及以上的个体使用高剂量 （HD） Fluzone 流感疫苗，因为过去的研究表明，与标准剂量 （SD） 制剂相比，它可以改善抗体反应和疫苗功效 （VE）。由于流感疫苗经常重新配制，因此监测 VE 的任何潜在变化至关重要。传统的疗效试验可能既昂贵又耗时。使用更新的配方进行免疫原性研究并使用结果数据估计 VE 是随着时间的推移评估这些疫苗的更有效方法。在流感疫苗研究中，血凝抑制 （HAI） 滴度被认为是保护的可靠相关性，以前曾用于估计 VE。方法 我们分析了在 2013/14 至 2021/22 流感季节接受 SD 或 HD Fluzone 分裂灭活流感疫苗的人类疫苗队列的数据。我们使用先前开发的统计模型将疫苗接种前和疫苗接种后的 HAI 滴度映射到保护概率，并计算了与同一年龄组和年轻 （<65） 成人相比，老年人 （65） 岁 HD 疫苗的疫苗效力 （VE） 的差异。结果我们发现，对于 65 岁及以上的参与者，HD 疫苗通常提高了不同季节的估计 VE。然而，我们还发现 HD 接受者的估计 VE 通常低于年轻的 SD 接受者。结论 虽然与 SD 相比，HD Fluzone 疫苗导致老年人的估计 VE 略有增加，但应考虑进一步增加剂量或其他发展以改善 VE。