Medical and Scientific Affairs, MedImmune, LLC, One MedImmune Way, Gaithersburg, MD 20878, USA.
Vaccine. 2012 Jan 20;30(5):886-92. doi: 10.1016/j.vaccine.2011.11.104. Epub 2011 Dec 7.
Nine randomized controlled clinical trials, including approximately 26,000 children aged 6 months to 17 years, have evaluated the efficacy of live attenuated influenza vaccine (LAIV) against culture-confirmed influenza illness compared with placebo or trivalent inactivated influenza vaccine (TIV). The objective of the current analysis was to integrate available LAIV efficacy data in children aged 2-17 years, the group for whom LAIV is approved for use.
A meta-analysis was conducted using all available randomized controlled trials and a fixed-effects model. Cases caused by drifted influenza B were analyzed as originally classified and with all antigenic variants classified as dissimilar.
Five placebo-controlled trials (4 were 2-season trials) and 3 single-season TIV-controlled trials were analyzed. Compared with placebo, year 1 efficacy of 2 doses of LAIV was 83% (95% CI: 78, 87) against antigenically similar strains; efficacy was 87% (95% CI: 78, 93), 86% (95% CI: 79, 91), and 76% (95% CI: 63, 84) for A/H1N1, A/H3N2, and B, respectively. Classifying B variants as dissimilar, efficacy against all similar strains was 87% (95% CI: 83, 91) and 93% (95% CI: 83, 97) against similar B strains. Year 2 efficacy was 87% (95% CI: 82, 91) against similar strains. Compared with TIV, LAIV recipients experienced 44% (95% CI: 28, 56) and 48% (95% CI: 38, 57) fewer cases of influenza illness caused by similar strains and all strains, respectively. LAIV efficacy estimates for children from Europe, the United States, and Middle East were robust and were similar to or higher than those for the overall population.
In children aged 2-17 years, LAIV demonstrated high efficacy after 2 doses in year 1 and revaccination in year 2, and greater efficacy compared with TIV. This meta-analysis provides precise estimates of LAIV efficacy among the approved pediatric age group.
有九项随机对照临床试验，包括约 26000 名 6 个月至 17 岁的儿童，评估了减毒活流感疫苗（LAIV）与安慰剂或三价灭活流感疫苗（TIV）相比对培养确诊的流感疾病的疗效。本分析的目的是整合可用于 2-17 岁儿童的现有 LAIV 疗效数据，这是 LAIV 获准使用的人群。
使用所有可用的随机对照试验和固定效应模型进行荟萃分析。最初分类的 B 型流感 drifted 引起的病例与所有抗原变异型被归类为不同的病例一起进行分析。
分析了 5 项安慰剂对照试验（其中 4 项为 2 季试验）和 3 项单季 TIV 对照试验。与安慰剂相比，2 剂 LAIV 在第 1 年的疗效为针对抗原相似株的 83%（95%CI：78，87）；针对 A/H1N1、A/H3N2 和 B 型的疗效分别为 87%（95%CI：78，93）、86%（95%CI：79，91）和 76%（95%CI：63，84）。将 B 型变异型归类为不同的，则针对所有相似株的疗效为 87%（95%CI：83，91）和 93%（95%CI：83，97）。第 2 年的疗效为针对相似株的 87%（95%CI：82，91）。与 TIV 相比，LAIV 受种者经历的由相似株引起的流感疾病病例分别减少了 44%（95%CI：28，56）和 48%（95%CI：38，57），由所有株引起的流感疾病病例分别减少了 44%（95%CI：28，56）和 48%（95%CI：38，57）。来自欧洲、美国和中东的儿童的 LAIV 疗效估计值是可靠的，与总体人群相比或高于总体人群。
在 2-17 岁儿童中，LAIV 在第 1 年接种 2 剂后和第 2 年加强免疫后具有高疗效，与 TIV 相比具有更高的疗效。本荟萃分析提供了在批准的儿科年龄组中 LAIV 疗效的精确估计。
