基于实验室检测结果病例⁃对照研究评价6~72月龄儿童流感疫苗效果

摘要

目的 评价6~72月龄儿童流感苗的疫苗效果.方法 采用基于实验室检测结果病例?对照研究(TNCC)设计,从中国流感监测信息系统中,选取2016年10月至2017年4月及2017年10月至2018年4月永康和义乌市6~72月龄流感样病例(ILI)为研究对象,共1 161例,将流感病毒阳性者作为病例组(403例),阴性者作为对照组(758例).从中国流感监测信息系统和免疫规划信息管理系统中获取研究对象的病原学和免疫接种资料,采用倾向评分(PS)法均衡TNCC研究中非随机化对照的混杂效应,采用多因素logistic回归模型,计算流感疫苗效果及其95%CI值.结果 研究对象的年龄为(2.44±1.60)岁,男童为681例(58.66%).病例组年龄为(2.62±1.58)岁,A(H3N2)亚型、甲型H1N1、B(Victoria)系、B(Yamagata)系和混合型感染分别为237例(58.81%)、92例(22.83%)、62例(15.38%)、11例(2.73%)和1例(0.25%);男童为246例(61.04%).对照组年龄为(2.35±1.61)岁,男童为435例(57.39%).2个流感流行季内,流感疫苗效果(95%CI)为58%(31%~74%),36~72月龄组流感疫苗效果(95%CI)为68%(41%~82%),而6~35月龄为28%(-80%~71%).2016—2017年流行季,流感疫苗效果(95%CI)为54%(16%~75%),对A(H3N2)亚型流感疫苗效果(95%CI)为65%(24%~83%).2017—2018年流行季,流感疫苗效果(95%CI)为69%(18%~88%).结论 流感流行季节内,流感疫苗效果较好,对6~72月龄儿童有一定保护效果,但对36~72月龄儿童保护效果高于6~35月龄儿童.%Objective To assess the effectiveness of seasonal influenza vaccine among children aged 6 to 72 months. Methods The test?negative case control study was conducted based on available surveillance data which was from China Influenza Surveillance Information system (CSIS). From October 2016 to April 2017 and from October 2017 to April 2018,1 161 cases aged 6-72 months with influenza?like illness in Yongkang and Yiwu city, were selected as the study subjects, and the cases with influenza test?positive were selected as the case group (403 cases). Test?negative subjects were selected as control group (758 cases). The etiology and immunization data of the subjects were obtained from CSIS and Immune Information and Management System (IIMS) respectively. Vaccine effectiveness was estimated using multivariate logistic regression model,and the mixed effects of non?randomized control in TNCC study were equalized by using the propensity score (PS) method in the statistical analysis. Results The age of the subjects was (2.44±1.60) years,and there were 681 boys (58.66%). The age of case group was (2.62±1.58) years, and there were 246 boys (61.04%). The case group was including of 237 cases (58.81%) of influenza A (H3N2), 92 cases (22.83%) of influenza A (H1N1) pmd09, 62 cases (15.38%) of influenza B(Victoria) lineage, 11 cases (2.73%) of influenza B (Yamagata) lineage and one case (0.25%) co?infection of influenza [A(H3N2)+B (Victoria)]. The mean age of the control group was (2.35±1.61) years,and there were 435 boys (57.39%). Overall vaccine effectiveness (VE) against all type influenza for two seasons combined was 58% (95%CI: 31%-74%). An analysis by age groups showed 68% (95%CI:41%-82%) of the VE estimate among children aged 36-72 months while it was 28%(95%CI : -80%-71%)of the VE estimate among children aged 6-35 months. The VE estimate value was 54% (95%CI:16%-75%) against all type influenza and 65% (95%CI:24%-83%) against influenza A (H3N2) during the 2016-2017 season. During the 2017-2018 season, the VE estimate value was 69% (95%CI: 18%-88%) against all type influenza. Conclusion Influenza vaccine is effective in preventing influenza virus infection during the flu season,especially the effect among children aged 36-72 months is higher compared to that among children aged 6-35 months.