基于倾向得分匹配的老年人接种流感疫苗对流感就诊的保护效果研究

目的 评估老年人接种流感疫苗对流感就诊的保护效果，并探讨倾向得分匹配法（PSM）在疫苗保护效果研究中的应用价值。方法 以成都市为研究现场，选取2017年9-12月间接种流感疫苗的60岁及以上老年人作为接种组，采用PSM法选取观察对象作为对照组。匹配后比较两组人群疫苗接种后一年内的流感就诊情况，评价疫苗保护效果。结果 流感疫苗接种组与未接种组各有1442例匹配成功。两组的一般人口学特征、生活方式及健康意识、基本健康状况等特征在匹配前有显著差异，匹配后两组协变量达到均衡。匹配后接种组和对照组流感就诊率分别为0.69%、2.84%，疫苗接种可减少之后一年内75.70%的流感就诊。结论 PSM可有效降低观察性研究组间的混杂偏倚，在疫苗接种效果评价中具有长远的应用价值。流感疫苗接种对降低≥60岁老年人流感就诊具有良好效果，今后有必要采取措施提高流感疫苗接种率。

Influenza vaccine effectiveness against influenza-related outpatient and inpatient visits among the elderly based on propensity score matching

To evaluate the influenza vaccine effectiveness against influenza －associated outpatient and inpatient visits among the elderly，and to validate the applicability of propensity score matching ( PSM) method in vaccine effectiveness ( VE) studies. Methods The elderly aged ≥60 years who had been received influenza vaccine during September to December in 2017 in Chengdu were selected into vaccinated group，and the PSM was performed to choose controls. The VE was accessed through comparing the difference in outpatient and inpatient visits within one year after vaccination between the two groups. Results There were significant differences between the vaccinated and unvaccinated objects in terms of general demographic characteristics，lifestyle，health awareness and health status，which were eliminated after matching. The final analysis included 1 442 cases and 1 442 matched controls. There was a significant evidence that vaccination could reduce the outpatient and inpatient visits due to influenza by 75. 70% ，from 2. 84% ( control group) and 0. 69% ( vaccinated group) . Conclusion PSM is beneficial for reducing confounding bias in observational studies and worth extended application. Influenza vaccinationcan help to reduce influenza－related outpatient and inpatient visits in the elderly，and efforts should therefore be paid to enhance vaccination uptake in the elderly.