奉化市人群麻疹抗体水平监测及初中学生麻疹疫苗加强接种效果观察

Measles Antibody Level in Population and Effects of Measles Booster Vaccination in Junior School Students,Fenghua City

目的分析奉化市1957-2006年麻疹流行病学特征,了解奉化市人群麻疹免疫水平及对初中学生加强接种麻疹疫苗后的免疫效果,为修定麻疹疫苗加强免疫方案提供客观依据。方法按照麻疹疫苗使用和计划免疫冷链装备情况将奉化市1957-2006年麻疹疫情划分为4个阶段进行比较;随机选取该市孕妇、婴幼儿、小学、初中、高中学生和育龄妇女共1500余人次进行麻疹IgG抗体监测,对2005年暴发过麻疹并进行过麻疹疫苗应急接种的西坞初中学生和2006年加强接种麻疹疫苗的莼湖初中学生进行免疫效果分析。麻疹IgG抗体检测采用ELISA定量法。结果4阶段麻疹年均发病率和年龄构成差异有统计学意义,发病年龄由幼儿和学龄前儿童为主,向8月龄以下小婴儿和15岁以上大年龄组人群转移;2005年该市本地人口8月龄以下小婴儿和15岁以上人群发病分别占25.86%和72.41%。6～8月龄婴儿麻疹IgG抗体GMC为51IU/L,8月龄婴儿麻疹疫苗初免成功率为100%,保护性抗体阳性率为94.12%,GMC为1352IU/L;18月复种后保护性抗体阳性率达100%,GMC为2333IU/L,小学高年级、初高中学生、育龄妇女及孕妇保护性抗体阳性率在46%～68%之间,GMC在783IU/L～901IU/L之间;西坞初中学生应急接种麻疹疫苗1年后保护性抗体阳性率为80.10%,GMC为1889IU/L,莼湖初中学生加强接种麻疹疫苗1月后保护性抗体阳性率为97.64%,GMC为2354IU/L。结论8月龄和18月龄麻疹疫苗初免和复种免疫效果良好,10岁以上人群麻疹IgG抗体水平下降,对初中学生进行麻疹疫苗加强接种免疫效果明显。建议调整现行麻疹的免疫策略,对初中学生进行麻疹疫苗加强接种,以削平大小两端年龄麻疹发病高峰,实现WHO西太区提出的到2012年消除麻疹的目标。

Objective To evaluate the measles antibody level of population and immune effect of the measles booster vaccination in junior school students in Fenghua city, and to provide objective basis for adjusting the current immune procedure. Methods According to the conditions of measles vaccine using and cold chain system status, the data of measles epidemic situation in 1957 -2006 were divided into four periods and analyzed. A total of 1 500 serum samples were collected from pregnant women, infants and children, students of primary, junior and senior schools, and women of childbearing age by random method, and detected for measles IgG antibody by ELISA; And the immunization effects of students of Xiwu Junior School who had been vaccinated with measles vaccine during the outbreak of measles in 2005 and those of Chunhu Junior School vaccinated with measles supplementary immunization in 2006 were evaluated. Results The incidences of measles and age composition were significantly changed in four periods. The main measles patients transfered from infants and preschool aged children to groups both aged under 8 months and over 15 years. In 2005, measles cases were mostly concentrated in residents aged under 8 months and over 15 years, accounting for 25.86% and 72. 41%, respectively. GMC of infants aged 6 - 8 months was 51 IU/L before immunization and increased to 1 352 IU/L after basic immunization. The immune successful rate of this group was 100% , and the positive rate of preventive antibody was 94. 12%. Re - immunization positive rate of preventive antibody 18 months later was 100%, with 2 333 IU/L of GMC; Positive rates of preventive antibody among students of primary, junior and senior schools, women of childbearing age and pregnant women were 46% - 68%, with 783 IU/L - 901 IU/L of GMC ; Positive rate of preventive antibody in Xiwu＇s students after 1 year of emergent vaccination was 80. 10%, with 1 889 IU/L of GMC. And the positive rate in Chunhu＇s students after 1 month of vaccination was 97.64%, with 2 354 IU/L of GMC. Condusion The effects of basic immunizationfor infants aged 8 months and re - immunization for children aged 18 months were satisfactory, but the level of measles antibody dropped along with aging. A booster measles vaccination to junior students had significant effects. The current measles immunication strategy should be adjusted by taking booster vaccination of measles for junior students so as to eliminate measles by 2012.