Instituto de Salud Publica de Navarra (Public Health Institute of Navarre), Pamplona, Spain.
Euro Surveill. 2013 Jan 31;18(5):20388. doi: 10.2807/ese.18.05.20388-en.
This study evaluates the influenza vaccine effectiveness (VE) in preventing laboratory-confirmed cases in Navarre, Spain, in the 2011/12 season in which the peak was delayed until week 7 of 2012. We conducted a test-negative case–control study. Patients with influenza-like illness in hospitals and primary healthcare were swabbed for testing by reverse transcription-polymerase chain reaction. Influenza vaccination status and other covariates were obtained from healthcare databases. The vaccination status of confirmed cases and negative controls was compared after adjusting for potential confounders. VE was calculated as (1-odds ratio)x100. The 411 confirmed cases (93% influenza A(H3)) were compared with 346 controls. Most characterised viruses did not match the vaccine strains. The adjusted estimate of VE was 31% (95% confidence interval (CI): -21 to 60) for all patients, 44% (95% CI: -11 to 72) for those younger than 65 years and 19% (95% CI: -146 to 73) for those 65 or older. The VE was 61% (95% CI: 5 to 84) in the first 100 days after vaccination, 42% (95% CI: -39 to 75) between 100 and 119 days, and zero thereafter. This decline mainly affected people aged 65 or over. These results suggest a low preventive effect of the 2011/12 seasonal influenza vaccine, and a decline in VE with time since vaccination.
本研究评估了西班牙纳瓦拉地区在 2011/12 流感季节中流感疫苗的有效性（VE），该地区的高峰期推迟到 2012 年第 7 周。我们进行了一项病例对照研究。在医院和初级保健机构中，有流感样症状的患者被采集样本进行逆转录-聚合酶链反应检测。从医疗保健数据库中获取流感疫苗接种情况和其他协变量。在调整潜在混杂因素后，比较确诊病例和阴性对照的疫苗接种情况。VE 计算为（1-比值比）x100。411 例确诊病例（93%为甲型 H3N2）与 346 例对照进行了比较。大多数特征病毒与疫苗株不匹配。所有患者的调整后 VE 估计值为 31%（95%置信区间（CI）：-21 至 60），年龄小于 65 岁的患者为 44%（95% CI：-11 至 72），年龄为 65 岁或以上的患者为 19%（95% CI：-146 至 73）。接种后 100 天内 VE 为 61%（95% CI：5 至 84），100 至 119 天为 42%（95% CI：-39 至 75），此后为零。这种下降主要影响 65 岁或以上的人群。这些结果表明 2011/12 季节性流感疫苗的预防效果较低，且 VE 随接种时间的推移而下降。
