深圳市南山区2021—2022年流感流行季中小学生接种流感疫苗效果评价

Influenza vaccine effectiveness in primary and secondary school students:an ILI surveillance-based test-negative design case-control study in a district of Shenzhen city during 2021-2022 influenza season

目的采用检测阴性设计(TND)病例对照研究评价中小学生接种灭活三价流感疫苗的保护效果(VE)。方法对深圳市南山区2021年11月—2022年5月综合医院发热门诊发现的286例6~15岁中小学生流感样病例(ILI)进行流感病毒核酸PCR检测,流感病毒核酸检测阳性者为阳性病例组,检测阴性者为阴性对照组,收集2组的流感疫苗接种记录,计算2组的流感疫苗接种比值比(OR)及VE。结果286例ILI中,流感病毒核酸检测阳性68例(23.78%),均为乙型流感,阴性218例(76.22%),病例组当季流感疫苗接种率为5.88%(4/68),对照组接种率为15.14%(33/218),OR值为0.3886(95%CI=0.1528~0.9880),VE为61.14%(95%CI=1.20%~84.72%)。结论接种当季流感疫苗可以保护中小学生感染流感,鼓励中小学生接种当季流感疫苗以预防流感。

Objective To evaluate the vaccine effectiveness(VE)of inactivated trivalent influenza vaccine in primary and secondary school students.Methods Respiratory specimens were detected with PCR for influenza virus nucleic acid among 286 primary and secondary school students(6-15 years old)diagnosed as influenza-like illness(ILI)cases at all fever clinics in Nanshan district of Shenzhen city during an influenza season(from November 2021 to May 2022)and the ILI cases’information on demography and influenza vaccination were collected simultaneously.The ILI cases positive for viral nucleic acid were assigned into a case group and those negative into a control group.Influenza vaccination ratio and odds ratio[OR]of viral nucleic acid positivity for the two groups were analyzed and compared to estimate the VE of influenza vaccination.Results Of the 286 ILI cases,68(23.78%)were positive for influenza nucleic acid(all belonging to B strain)and 218(76.22%)were negative.The ratio of seasonal influenza vaccination was 5.88%(4/64)for the cases and 15.14%(33/216)for the controls,and the OR of being virus nucleic acid positive was 0.3886(95%confidence interval[CI]:0.1528-0.9880)for the vaccinated ILI cases.The estimated VE was 61.14%(95%CI:1.20%-84.72%)for seasonal influenza vaccination.Conclusion Seasonal influenza vaccination can protect primary and secondary school students from influenza virus infection.The result suggests that seasonal influenza vaccination needs to be promoted among school age children.