Immunization Unit, Department of Infectious Disease Epidemiology, Robert Koch Institute, DGZ-Ring 1, 13086 Berlin, Germany.
BMC Infect Dis. 2012 May 31;12:127. doi: 10.1186/1471-2334-12-127.
We performed a case-control study to estimate vaccine effectiveness (VE) for prevention of hospitalization due to pandemic influenza A(H1N1)pdm09 (pH1N1) and to identify risk factors for pH1N1 and acute respiratory infection (ARI) in 10 hospitals in Berlin from December 2009 to April 2010.
Cases were patients aged 18-65 years with onset of ARI ≤10 days before admission testing positive for pH1N1 by PCR performed on nasal and throat swabs or by serological testing. Cases were compared to (1) matched hospital controls with acute surgical, traumatological or other diagnoses matched on age, sex and vaccination probability, and (2) ARI patients testing negative for pH1N1. Additionally, ARI cases were compared to matched hospital controls. A standardized interview and chart review elicited demographic and clinical data as well as potential risk factors for pH1N1/ARI. VE was estimated by 1-(Odds ratio) for pH1N1-vaccination ≥10 days before symptom onset using exact logistic regression analysis.
Of 177 ARI cases recruited, 27 tested pH1N1 positive. A monovalent AS03-adjuvanted pH1N1 vaccine was the only pandemic vaccine type identified among cases and controls (vaccination coverage in control group 1 and 2: 15% and 5.9%). The only breakthrough infections were observed in 2 of 3 vaccinated HIV positive pH1N1 patients. After exclusion of HIV positive participants, VE was 96% (95%CI: 26-100%) in the matched multivariate analysis and 46% (95%CI: -376-100%) in the test-negative analysis. Exposure to children in the household was independently associated with hospitalization for pH1N1 and ARI.
Though limited by low vaccination coverage and number of pH1N1 cases, our results suggest a protective effect of the AS03-adjuvanted pH1N1 vaccine for the prevention of pH1N1 hospitalization. The use of hospital but not test-negative controls showed a statistically protective effect of pH1N1-vaccination and permitted the integrated assessment of risk factors for pH1N1-infection. To increase statistical power and to permit stratified analyses (e.g. VE for specific risk groups), the authors suggest pooling of future studies assessing effectiveness of influenza vaccines for prevention of severe disease from different centres.
我们进行了一项病例对照研究，以评估 2009 年 12 月至 2010 年 4 月期间柏林 10 家医院因大流行性甲型 H1N1(pdm09)(pH1N1)住院的疫苗有效性(VE)，并确定 pH1N1 和急性呼吸道感染(ARI)的危险因素。
病例为年龄在 18-65 岁之间的患者，ARI 发病≤入院前 10 天，经鼻喉拭子 PCR 或血清学检测 pH1N1 阳性。病例与(1)年龄、性别和接种概率相匹配的有急性外科、创伤或其他诊断的医院对照，(2)pH1N1 检测阴性的 ARI 患者进行比较。此外，还将 ARI 病例与匹配的医院对照进行比较。标准化访谈和图表回顾收集人口统计学和临床数据以及 pH1N1/ARI 的潜在危险因素。使用精确逻辑回归分析，在症状出现前 10 天以上，使用 pH1N1 疫苗接种的 1-(优势比)估计 VE。
在招募的 177 例 ARI 病例中，27 例 pH1N1 检测阳性。在病例和对照组中，仅发现单价 AS03 佐剂 pH1N1 疫苗是唯一的大流行疫苗类型(对照组 1 和 2 的疫苗接种率分别为 15%和 5.9%)。仅在 2 例接受疫苗的 HIV 阳性 pH1N1 患者中观察到突破性感染。排除 HIV 阳性参与者后，在匹配的多变量分析中 VE 为 96%(95%CI：26-100%)，在阴性测试分析中 VE 为 46%(95%CI：-376-100%)。家中有儿童接触与 pH1N1 和 ARI 住院有关。
尽管疫苗接种率和 pH1N1 病例数量有限，但我们的结果表明 AS03 佐剂 pH1N1 疫苗对预防 pH1N1 住院具有保护作用。使用医院而非阴性检测对照显示 pH1N1 疫苗接种具有统计学上的保护作用，并允许综合评估 pH1N1 感染的危险因素。为了提高统计能力并允许进行分层分析(例如，针对特定风险群体的 VE)，作者建议汇集来自不同中心评估流感疫苗预防严重疾病效果的未来研究。
