基于检测阴性设计2011—2021年儿童流感疫苗保护效果评价

Influenza vaccine effectiveness among children,2011-2021:a test-negative design-based evaluation

目的评价2011—2021年6~59月龄儿童流感疫苗接种对实验室确诊流感的保护效果,为流感疫苗接种建议和政策制定提供数据支持。方法基于2011年10月—2021年5月在苏州大学附属儿童医院开展的流感前瞻性监测,采用检测阴性设计的病例对照研究方法,将流感阳性病例和阴性对照按年龄和就诊或住院日期进行1:2匹配,使用条件logistic回归分析计算疫苗接种的调整OR值(a OR),并估计流感疫苗效果。结果共监测到符合纳入标准的流感样病例(ILI)5554例,严重呼吸道感染(SARI)病例7737例,在73.3%(9747/13291)查询到疫苗接种记录的研究对象中,当前流感季疫苗接种率为1.79%(174/9747)。流感疫苗总体保护效果为36.8%(95%CI=-4.7%~61.9%),对ILI和SARI的保护效果分别为26.7%(95%CI=-34.8%~60.2%)和53.1%(95%CI=-17.0%~81.2%);对6~35月龄和36~59月龄儿童的保护效果分别为28.9%(95%CI=-31.2%~61.5%)和51.2%(95%CI=-21.3%~80.4%);对6~35月龄儿童,部分接种和完全接种的保护效果分别为21.6%(95%CI=-65.1%~62.7%)和40.6%(95%CI=-66.0%~78.8%)。结论流感疫苗总体保护效果为36.8%,对SARI的保护效果优于对ILI的保护效果,对36~59月龄儿童的保护效果优于对6~35月龄儿童的保护效果;对6~35月龄儿童,完全接种的保护效果优于部分接种。

Objective To evaluate influenza vaccine effectiveness(VE)in preventing laboratory confirmed influenza illness among children aged 6-59 months during 2011-2021,and to provide evidences for improving vaccination recommendation and policy-making.Methods Based on a prospective influenza surveillance conducted at the Soochow University Affiliated Children′s Hospital in Suzhou city,Jiangsu province from October 2011 to May 2021,we conducted a test-negative case-control study.The participants of the study were selected from 5554 influenza-like illness(ILI)and 7737severe acute respiratory infection(SARI)outpatients/inpatients aged 6-59 months and with nasopharyngeal swab/sputum specimen test for influenza virus nucleic acid in the surveillance and influenza vaccination records of all the ILI and SARI patients were checked retrospectively.The cases of the study were influenza virus-positive ILI(n=517)and SARI(n=582)patients aged 6-59 months;the controls were 1:2 age-and clinic attending/hospital admission date-matched influenza virus-negative ILI/SARI patients.The adjusted odds ratio(a OR)of vaccination and VE were estimated using conditional logistic regression.Results The vaccination records were available for 73.3%(9747)of the registered patients and the observed vaccination rate was 1.79%(174/9747).The overall VE for all the ILI/SARI patients was 36.8%(95% confidence interval[95%CI]:-4.7%-61.9%);the VE was 26.7%(95%CI:-34.8%-60.2%)for the ILI and 53.1%(95%CI:-17.0%-81.2%)for the SARI.The VE were 28.9%(95%CI:-31.2%-61.5%)and 51.2%(95%CI:-21.3%-80.4%)for the patients aged 6-35 months and 36-59 months.The VE of partial vaccination and full vaccination for children aged 6-35 months were 21.6%(95%CI=-65.1%-62.7%)and 40.6%(95%CI=-66.0%-78.8%),respectively.Conclusion The overall VE of influenza vaccination was 36.8% among 6-59 months old children,with a higher VE against SARI than that against ILI and a higher VE among the children aged 36-59 months than that among those aged 6-35 months.Full dose influenza vaccination provided better protection than partial dose vaccination for children aged 6-35 months.