摘要目的:估算北京市怀柔区2017—2019年流感流行季季节性流感疫苗对流感引起的住院严重急性呼吸道感染（severe acute respiratory infection，SARI）的保护效果（vaccine effectiveness，VE）。方法:利用2017—2019年流感流行季怀柔区住院SARI监测数据，采用检测阴性的病例对照设计，计算流感核酸阳性组与阴性组SARI患者流感疫苗接种的比值比（odds ratio， OR）以及VE。 结果:2017—2018年、2018—2019年流行季季节性流感疫苗对流感相关住院SARI的保护效果分别为：72.3%（95% CI：20.6%~90.4%）、-15.4%（95% CI：-202.4%~56.0%）。2017—2018年流行季中，流感疫苗对甲型H1N1流感的保护效果较好，为91.0%（95% CI：25.6%~98.9%）。 结论:2017—2018年季节性流感疫苗对预防流感相关的住院SARI有较好的效果，但2018—2019年的保护效果不明显。

abstractsObjective:To estimate the vaccine effectiveness (VE) of seasonal influenza vaccine in preventing influenza associated hospitalization of severe acute respiratory infection (SARI) in 2017~2019 influenza season in Huairou district of Beijing.Method:SARI surveillance data in one sentinel hospital of Huarou District from 2017 to 2019 were used to calculate vaccination odds ratio ( OR) and VE of SARI cases in influenza virus nucleic acid positive group and negative group, using the test-negative case control study method. Results:The estimations of VE against influenza associated hospitalization for SARI was 72.3% (95% CI: 20.6%-90.4%) and -15.4% (95% CI: -202.4%-56.0%) for the 2017-2018 influenza season and the 2018-19 season, respectively. During 2017-18 influenza season, the estimated VE against influenza A(H1N1)pdm09 was 91.0% (95% CI: 25.6%-98.9%). Conclusions:The seasonal influenza vaccine of 2017-2018 season showed good VE against influenza associated hospitalization for SARI while the VE in 2018-2019 season was not obvious.