University of Michigan School of Public Health, Ann Arbor.
Clalit Health Services, Clalit Research Institute, Tel Aviv.
Clin Infect Dis. 2019 Nov 27;69(12):2153-2161. doi: 10.1093/cid/ciz125.
Influenza vaccine effectiveness (VE) varies by season, circulating influenza strain, age, and geographic location. There have been few studies of influenza VE among hospitalized children, particularly in Europe and the Middle East.
We estimated VE against influenza hospitalization among children aged 6 months to 8 years at Clalit Health Services hospitals in Israel in the 2015-2016, 2016-2017, and 2017-2018 influenza seasons, using the test-negative design. Estimates were computed for full and partial vaccination.
We included 326 influenza-positive case patients and 2821 influenza-negative controls (140 case patients and 971 controls from 2015-2016, 36 case patients and 1069 controls from 2016-2017, and 150 case patients and 781 controls from 2017-2018). Over all seasons, VE was 53.9% for full vaccination (95% confidence interval [CI], 38.6%-68.3%), and 25.6% for partial vaccination (-3% to 47%). In 2015-2016, most viruses were influenza A(H1N1) and vaccine lineage-mismatched influenza B/Victoria; the VE for fully vaccinated children was statistically significant for influenza A (80.7%; 95% CI, 40.3%-96.1%) but not B (23.0%; -38.5% to 59.4%). During 2016-2017, influenza A(H3N2) predominated, and VE was (70.8%; 95% CI, 17.4%-92.4%). In 2017-2018, influenza A(H3N2), H1N1 and lineage-mismatched influenza B/Yamagata cocirculated; VE was statistically significant for influenza B (63.0%; 95% CI, 24.2%-83.7%) but not influenza A (46.3%; -7.2% to 75.3%).
Influenza vaccine was effective in preventing hospitalizations among fully vaccinated Israeli children over 3 influenza seasons, but not among partially vaccinated children. There was cross-lineage protection in a season where the vaccine contained B/Victoria and the circulating strain was B/Yamagata, but not in a season with the opposite vaccine-circulating strain distribution.
流感疫苗的有效性（VE）因季节、流行的流感病毒株、年龄和地理位置而异。关于住院儿童的流感 VE 研究较少，特别是在欧洲和中东地区。
我们使用病例对照研究方法，在以色列克拉利特健康服务医院（Clalit Health Services），估计了 2015-2016 年、2016-2017 年和 2017-2018 年三个流感季节中 6 个月至 8 岁儿童因流感住院的 VE。计算了完全和部分接种疫苗的估计值。
我们纳入了 326 例流感阳性病例患者和 2821 例流感阴性对照者（2015-2016 年有 140 例病例患者和 971 例对照者，2016-2017 年有 36 例病例患者和 1069 例对照者，2017-2018 年有 150 例病例患者和 781 例对照者）。所有季节的完全接种疫苗 VE 为 53.9%（95%置信区间[CI]，38.6%-68.3%），部分接种疫苗 VE 为 25.6%（-3%至 47%）。在 2015-2016 年，大多数病毒为甲型流感（H1N1）和疫苗谱系不匹配的乙型流感/B维多利亚；完全接种疫苗的儿童对甲型流感的 VE 具有统计学意义（80.7%；95% CI，40.3%-96.1%），但对乙型流感无统计学意义（23.0%；-38.5%至 59.4%）。在 2016-2017 年，甲型流感（H3N2）占主导地位，VE 为 70.8%（95% CI，17.4%-92.4%）。在 2017-2018 年，甲型流感（H3N2）、H1N1 和谱系不匹配的乙型流感/Yamagata 共同流行；乙型流感的 VE 具有统计学意义（63.0%；95% CI，24.2%-83.7%），但甲型流感的 VE 无统计学意义（46.3%；-7.2%至 75.3%）。
在 3 个流感季节中，流感疫苗对完全接种疫苗的以色列儿童住院有预防作用，但对部分接种疫苗的儿童无预防作用。在疫苗含有乙型流感/B维多利亚而流行株为乙型流感/Yamagata 的季节，存在交叉谱系保护，但在疫苗流行株分布相反的季节则没有。
