University of Michigan School of Public Health, Department of Epidemiology, Ann Arbor, Michigan, USA.
US Department of Veterans Affairs, Ann Arbor, Michigan, USA.
Clin Infect Dis. 2021 Oct 5;73(7):1248-1256. doi: 10.1093/cid/ciab395.
The evidence that influenza vaccination programs regularly provide protection to unvaccinated individuals (ie, indirect effects) of a community is lacking. We sought to determine the direct, indirect, and total effects of influenza vaccine in the Household Influenza Vaccine Evaluation (HIVE) cohort.
Using longitudinal data from the HIVE cohort from 2010-11 through 2017-18, we estimated direct, indirect, and total influenza vaccine effectiveness (VE) and the incidence rate ratio of influenza virus infection using adjusted mixed-effect Poisson regression models. Total effectiveness was determined through comparison of vaccinated members of full or partially vaccinated households to unvaccinated individuals in completely unvaccinated households.
The pooled, direct VE against any influenza was 30.2% (14.0-43.4). Direct VE was higher for influenza A/H1N1 43.9% (3.9 to 63.5) and B 46.7% (17.2 to 57.5) than A/H3N2 31.7% (10.5 to 47.8) and was higher for young children 42.4% (10.1 to 63.0) than adults 18.6% (-6.3 to 37.7). Influenza incidence was highest in completely unvaccinated households (10.6 per 100 person-seasons) and lower at all other levels of household vaccination coverage. We found little evidence of indirect VE after adjusting for potential confounders. Total VE was 56.4% (30.1-72.9) in low coverage, 43.2% (19.5-59.9) in moderate coverage, and 33.0% (12.1 to 49.0) in fully vaccinated households.
Influenza vaccines may have a benefit above and beyond the direct effect but that effect in this study was small. Although there may be exceptions, the goal of global vaccine recommendations should remain focused on provision of documented, direct protection to those vaccinated.
缺乏社区内流感疫苗接种项目定期为未接种人群（即间接效应）提供保护的证据。我们旨在通过 Household Influenza Vaccine Evaluation（HIVE）队列确定流感疫苗的直接、间接和总体效果。
使用 2010-11 年至 2017-18 年 HIVE 队列的纵向数据，我们使用调整后的混合效应泊松回归模型估计了流感疫苗的直接、间接和总体有效性（VE）以及流感病毒感染的发病率比值。总有效性是通过比较完全或部分接种家庭的接种成员与完全未接种家庭的未接种个体来确定的。
pooled，针对任何流感的直接 VE 为 30.2%（14.0-43.4）。流感 A/H1N1 的直接 VE 较高，为 43.9%（3.9-63.5）和 B 为 46.7%（17.2-57.5），而 A/H3N2 的直接 VE 为 31.7%（10.5-47.8），儿童的直接 VE 较高，为 42.4%（10.1-63.0），而成年人的直接 VE 为 18.6%（-6.3-37.7）。流感发病率在完全未接种家庭中最高（每 100 人-季节 10.6 例），而在所有其他家庭接种率水平则较低。在调整了潜在混杂因素后，我们几乎没有发现间接 VE 的证据。低覆盖率时的总 VE 为 56.4%（30.1-72.9），中覆盖率时为 43.2%（19.5-59.9），完全接种家庭时为 33.0%（12.1-49.0）。
流感疫苗的效果可能超出直接效果，但在本研究中，这种效果很小。尽管可能存在例外，但全球疫苗建议的目标仍应集中在为接种者提供有记录的直接保护。
