S191株麻疹疫苗对陕西省麻疹流行株的血清学效果研究

目的]分析陕西省近年麻疹流行的疫苗免疫因素，研究现行麻疹疫苗对流行株的实际保护效果。方法]用微量中和试验测定麻疹疫苗免疫血清和麻疹病人急性期血清对麻疹疫苗株和野毒株的中和抗体水平。结果]健康儿童麻疹疫苗免疫血清和有免疫史的麻疹病人急性期血清对麻疹野毒株的中和抗体几何平均滴度（GMT）分别为61．04、30．24，明显低于对S191株的GMT105．61、83．72），S191株中和抗体效价≤8的健康儿童疫苗免疫血清中，有16．7％野毒株中和抗体阴性。结论]由于麻疹流行株的抗原变异导致现行麻疹疫苗的保护力可能有所下降。

Study on Immunoprotecive Efficacy of S191 Measles Vaccine to the Epidemic Strains in Shanxi

Objective]To Analyze the immunity of measles vaccines in Shanxi province to learn immunoprotecive efficacy of current measles vaccines.Methods]Neutralization antibody level of measles vaccine virus and for wild measles virus in sera from healthy children and acute measles patients were determined by trace neutralization test.Results]NT antibody geometric mean titer(GMT) in the serum of vaccines and naturally infected individuals with the history of immunization to anti-wild type measles virus was 61.04 and 30.24 respectively,which was obviously lower than the GMT to S191(GMT was 105.61 and 83.72 respectively).The antibody negative rate against wild strain was 16.7% to these sera with the history of measles vaccination,and antibody potency against S191 strain less than 8.Conclusion]Antigenic variation of wild-type measles virus that circulated in Shanxi presented obviously and immunoprotecive efficacy of measles vaccine was partly influenced.