Health Protection Services - Colindale, Health Protection Agency, England.
Epidemiol Infect. 2014 Jan;142(1):126-33. doi: 10.1017/S0950268813000824. Epub 2013 Apr 16.
Methods for estimating vaccine effectiveness (VE) against severe influenza are not well established. We used the screening method to estimate VE against influenza resulting in intensive care unit (ICU) admission in England and Scotland in 2011/2012. We extracted data on confirmed influenza ICU cases from severe influenza surveillance systems, and obtained their 2011/2012 trivalent influenza vaccine (TIV) status from primary care. We compared case vaccine uptake with population vaccine uptake obtained from routine monitoring systems, adjusting for age group, specific risk group, region and week. Of 60 influenza ICU cases reported, vaccination status was available for 56 (93%). Adjusted VE against ICU admission for those aged ≥ 65 years was -10% [95% confidence interval (CI) -207 to 60], consistent with evidence of poor protection from the 2011/2012 TIV in 2011/2012. Adjusted VE for those aged <65 years in risk groups was -296% (95% CI -930 to -52), suggesting significant residual confounding using the screening method in those subject to selective vaccination.
针对严重流感的疫苗效力（VE）估计方法尚未得到很好的确立。我们使用筛选方法来估计英格兰和苏格兰 2011/2012 年因流感导致重症监护病房（ICU）入院的 VE。我们从严重流感监测系统中提取了确诊流感 ICU 病例的数据，并从初级保健中获得了他们在 2011/2012 年接种三价流感疫苗（TIV）的情况。我们将病例疫苗接种率与常规监测系统获得的人群疫苗接种率进行了比较，同时考虑了年龄组、特定风险组、地区和周次。在报告的 60 例流感 ICU 病例中，有 56 例（93%）可获得疫苗接种情况。对于年龄≥65 岁的人群，调整后的 ICU 入院 VE 为-10%[95%置信区间（CI）-207 至 60]，与 2011/2012 年 TIV 对 2011/2012 年的保护效果不佳一致。对于年龄<65 岁且处于风险组的人群，调整后的 VE 为-296%（95%CI-930 至-52），表明在接受选择性疫苗接种的人群中，使用筛选方法存在明显的残余混杂。
