British Columbia Centre for Disease Control, Vancouver, BC, Canada.
BMJ. 2011 Feb 3;342:c7297. doi: 10.1136/bmj.c7297.
To assess the effectiveness of the pandemic influenza A/H1N1 vaccine used in Canada during autumn 2009.
Test negative incident case-control study based on sentinel physician surveillance system.
Community based clinics contributing to sentinel networks in British Columbia, Alberta, Ontario, and Quebec, Canada.
552 patients who presented to a sentinel site within seven days of onset of influenza-like illness during the primary analysis period between 8 November and 5 December 2009; participants were mostly (>80%) children and adults under 50 years old.
Monovalent AS03 adjuvanted pandemic influenza A/H1N1 vaccine as the predominant formulation (>95%) distributed in Canada.
Vaccine effectiveness calculated as 1-(odds ratio for influenza in vaccinated (received pandemic H1N1 vaccine at least two weeks before onset of influenza-like illness) versus unvaccinated participants), with adjustment for age, comorbidity, province, timeliness of specimen collection, and week of illness onset. Sensitivity analyses explored the influence of varying analysis periods between 1 November and 31 December, receipt of trivalent seasonal influenza vaccine, and restriction to participants without comorbidity.
During the primary analysis period, pandemic H1N1 was detected by reverse transcription polymerase chain reaction in 209/552 (38%) participants; rates were highest in children and young adults (40%) and lowest in people aged 65 or over (9%). Among the 209 cases, 35 (17%) reported comorbidity compared with 80/343 (23%) controls. Two (1%) cases had received pandemic H1N1 vaccine at least two weeks before the onset of illness, compared with 58/343 (17%) controls, all single dose. Adjusted vaccine effectiveness overall was 93% (95% confidence interval 69% to 98%). High estimates of vaccine protection-generally at least 90%-were maintained across most sensitivity analyses.
Although limited by a small number of vaccine failures, this study suggests that the monovalent AS03 adjuvanted vaccine used in Canada during autumn 2009 was highly effective in preventing medically attended, laboratory confirmed pandemic H1N1 illness, with reference in particular to a single dose in children and young adults.
评估加拿大 2009 年秋季使用的甲型 H1N1 流感大流行疫苗的有效性。
基于哨点医生监测系统的阴性病例对照试验。
不列颠哥伦比亚省、艾伯塔省、安大略省和魁北克省参与哨点网络的社区诊所。
2009 年 11 月 8 日至 12 月 5 日主要分析期间，552 例流感样疾病发病后 7 天内到哨点就诊的患者；参与者主要为（>80%）儿童和 50 岁以下成年人。
单剂 AS03 佐剂甲型 H1N1 大流行疫苗，为加拿大主要分配疫苗（>95%）。
疫苗效力计算为接种疫苗的流感患者（在流感样疾病发病前至少 2 周接种大流行 H1N1 疫苗）与未接种疫苗患者的比值（优势比），调整年龄、合并症、省份、标本采集及时性和发病周。敏感性分析探讨了在 11 月 1 日至 12 月 31 日期间分析期的变化、三价季节性流感疫苗的接种和无合并症患者的限制对结果的影响。
在主要分析期间，552 例患者中有 209 例（38%）通过逆转录聚合酶链反应检测到甲型 H1N1 ；儿童和青年（40%）的发生率最高，65 岁及以上人群（9%）最低。209 例病例中，35 例（17%）报告合并症，而 343 例对照中 80 例（23%）报告合并症。2 例（1%）病例在发病前至少 2 周接种了大流行 H1N1 疫苗，而 343 例对照中有 58 例（17%），均为单剂。总体调整后的疫苗效力为 93%（95%置信区间 69%至 98%）。在大多数敏感性分析中，疫苗保护的高估计值（一般至少 90%）保持不变。
尽管疫苗失败的数量有限，但本研究表明，加拿大 2009 年秋季使用的单剂 AS03 佐剂疫苗在预防有医疗记录的实验室确诊甲型 H1N1 疾病方面非常有效，特别是对儿童和青年的单剂疫苗。
