为探讨山东省中小学生麻疹爆发的原因 ,采用 1∶2配比的病例对照方法对中小学生麻疹疫苗 (MV)效力进行了研究 ,同时对近年来中小学生MV接种率进行了估算。结果显示 :中小学生MV效力为 74 % ,95 %可信区间为4 7%～ 88% ;小学生MV效力明显高于中学生 ,分别为 82 %和 6 8% ;1999～ 2 0 0 1年学龄儿童的估算接种率分别为75 4 %、75 6 %和 5 5 7%。较低的MV效力和接种率是计划免疫工作薄弱地区中小学生麻疹爆发的主要原因。 In order to explore the causes of measles outbreak in primary and secondary school students in Shandong Province, the efficacy of measles vaccine (MV) in primary and secondary schools was studied by using a 1: 2 ratio of case-control study. Meanwhile, MV vaccination rates of primary and secondary school students were estimated. The results showed that: MV effectiveness of primary and secondary school students was 74%, 95% confidence interval of 47% to 88%; pupils MV efficacy was significantly higher than secondary school students were 82% and 68%; 1999 ~ 2001 school-age children The estimated vaccination rates were 75 4%, 75 6% and 57 57% respectively. Lower MV efficacy and vaccination rates are the main cause of measles outbreaks among primary and secondary school students in areas where immunization is planned.