Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA.
Department of Family Medicine, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
Influenza Other Respir Viruses. 2020 Jul;14(4):380-390. doi: 10.1111/irv.12741. Epub 2020 Apr 16.
Influenza vaccination is recommended for all US residents aged ≥6 months. Vaccine effectiveness (VE) varies by age, circulating influenza strains, and the presence of high-risk medical conditions. We examined site-specific VE in the US Influenza VE Network, which evaluates annual influenza VE at ambulatory clinics in geographically diverse sites.
Analyses were conducted on 27 180 outpatients ≥6 months old presenting with an acute respiratory infection (ARI) with cough of ≤7-day duration during the 2011-2016 influenza seasons. A test-negative design was used with vaccination status defined as receipt of ≥1 dose of any influenza vaccine according to medical records, registries, and/or self-report. Influenza infection was determined by reverse-transcription polymerase chain reaction. VE estimates were calculated using odds ratios from multivariable logistic regression models adjusted for age, sex, race/ethnicity, time from illness onset to enrollment, high-risk conditions, calendar time, and vaccination status-site interaction.
For all sites combined, VE was statistically significant every season against all influenza and against the predominant circulating strains (VE = 19%-50%) Few differences among four sites in the US Flu VE Network were evident in five seasons. However, in 2015-16, overall VE in one site was 24% (95% CI = -4%-44%), while VE in two other sites was significantly higher (61%, 95% CI = 49%-71%; P = .002, and 53%, 95% CI = 33,67; P = .034).
With few exceptions, site-specific VE estimates aligned with each other and overall VE estimates. Observed VE may reflect inherent differences in community characteristics of the sites and highlights the importance of diverse settings for studying influenza vaccine effectiveness.
美国建议所有≥6 个月龄的居民接种流感疫苗。疫苗有效性（VE）因年龄、流行的流感毒株和存在高风险的医疗条件而有所不同。我们在美国流感 VE 网络中检查了特定地点的 VE，该网络评估了在地理分布广泛的地点进行的门诊诊所的年度流感 VE。
在 2011-2016 年流感季节，对 27180 名≥6 个月大的患有急性呼吸道感染（ARI）且咳嗽持续时间≤7 天的门诊患者进行了分析。采用病例对照设计，根据病历、登记处和/或自我报告，将接种状态定义为接受了≥1 剂任何流感疫苗。通过逆转录聚合酶链反应确定流感感染。使用多变量逻辑回归模型调整年龄、性别、种族/族裔、发病到就诊时间、高风险状况、日历时间和接种状态-地点交互作用后计算 VE 估计值。
在所有地点合并的情况下，每个季节的 VE 针对所有流感和主要流行株都是有统计学意义的（VE=19%-50%）。在美国 Flu VE 网络的四个地点中，很少有差异在五个季节中显现出来。然而，在 2015-16 年，一个地点的总体 VE 为 24%（95%CI=-4%-44%），而其他两个地点的 VE 明显更高（61%，95%CI=49%-71%；P=0.002，53%，95%CI=33,67；P=0.034）。
除了少数例外，特定地点的 VE 估计值彼此一致，并且与总体 VE 估计值一致。观察到的 VE 可能反映了各地点社区特征的固有差异，并强调了在研究流感疫苗有效性时使用多样化设置的重要性。
