Objective: To investigate the immunogenicity and safety of a boost dose of measles, mumps, and rubella combined vaccine (MMR) for children 4 to 6 years old. Methods: Children, aged 4 to 6 years old, had vaccinated with 1 dose of measles and rubella combined vaccine(MR) at the age of 8 months and 1 dose of MMR vaccine at 18-months, were recruited in Shanxi, Inner Mongolia, and Beijing, respectively. All children were assigned into 4, 5 and 6-year-old group. The children who met inclusion and exclusion criteria were vaccinated with 1 dose MMR vaccine, and were collected blood samples before vaccination and 35 to 42 d after the vaccination. During the study period, adverse events were collected at 30 min, 1 d, 2 d, 3 d, 4-12 d, and 13 to 42 days after vaccination. Serum was tested for IgG antibodies against measles, mumps and rubella. Geometric mean concentrations (GMC) of measles, mumps, and rubella antibodies were compared among groups by analysis of variance or non-parametric test. Seropositive rates and adverse event rates were compared among groups by Chi-square test or Fisher exact test. Results: A total of 500 children were included in immunogenicity analysis and 535 children were included in safety analysis. The overall adverse event rate was 20.37%, the most of severity for adverse events was mild. The rates of local and systemic adverse events were 0.37% and 20.00%, respectively. Symptoms of local adverse events were redness. The main systemic adverse events were fever, followed by cough, rash and runny nose. Received a dose of MMR vaccine for booster immunization, the seropositive rates of measles antibody, mumps antibody and rubella antibody were above 99% for all 3 age groups, and there was no significant difference between groups. There were significant differences in mumps antibody GMC among groups (P=0.042), but no significant differences in measles and rubella antibodies GMC. Conclusion: The immunogenicity and safety of a boosted MMR vaccintion in children aged 4, 5 and 6 years were all similar good.
目的： 探讨4~6岁儿童接种麻疹-流行性腮腺炎-风疹联合减毒活疫苗（MMR）后的加强免疫原性与安全性。 方法： 分别在山西省、内蒙古自治区以及北京市招募曾有8月龄和18月龄接种过1剂麻疹-风疹联合减毒活疫苗和MMR疫苗免疫史的4~6岁儿童作为研究对象，分为4、5、6岁组，进行MMR疫苗加强免疫研究。接种MMR疫苗前与接种后35~42 d各采集血标本3 ml。在研究期间，主动监测疫苗接种后30 min、1 d、2 d、3 d、4~12 d，以及13~42 d的不良事件。血清采用酶标法检测麻疹、流行性腮腺炎和风疹的IgG抗体。采用方差分析或非参数检验比较研究组间麻疹、腮腺炎和风疹抗体几何平均浓度（GMC），采用χ2检验或Fisher确切概率法比较组间阳性率和不良事件发生率。 结果： 共500名完成免后采血儿童纳入免疫原性分析，535名儿童纳入安全性分析。总体不良事件发生率为20.37%，轻度不良事件最多。局部与全身不良事件发生率分别为0.37%和20.00%。局部不良事件的症状以接种部位发红为主，全身不良事件以发热症状为主，其次为咳嗽、皮疹、流涕等。在4~6岁进行1剂MMR疫苗加强免疫后，麻疹抗体、腮腺炎抗体与风疹抗体阳性率均在99%以上，3组间阳性率差异无统计学意义。3组间仅腮腺炎抗体GMC差异有统计学意义（P=0.042），麻疹与风疹抗体相关结果均无差异。免前阴性者的麻疹、腮腺炎及风疹抗体GMC均低于免前阳性者。 结论： 在4~6岁儿童中进行MMR疫苗的加强免疫，具有良好的免疫原性与安全性，在4~6岁之间的加强免疫效果相近。.