BRDⅡ株风疹减毒活疫苗免疫持久性观察

Immunopersistent of Attenuated Live Rubella Vaccine Prepared with BRD Ⅱ Strain

应用BRDⅡ株26代、28代和31代风疹减毒活疫苗对风疹血凝抑制（HI）抗体阴性的551名1～6岁儿童进行了免疫效果观察。3批疫苗免局42天抗体阳转率分别为98．0％、96.8％和96.4％，抗体GMT分别为115.1、100.9和94．8，表明BRDⅡ株具有良好的免疫原性。3批疫苗的抗体GMT逐年下降，到第3年分别为34、4、36．9和31．2，但各批间差异无显著意义。免后3年，26代和28代疫苗的抗体阳性率仍保持在95％以上，而31代疫苗的抗体阳性率下降至89．2％，明显低于其它两批疫苗。

551 children (aged 1~6 years) without HI antibodies to rubella were inmmunized with 3 lots of attenuated live rubella vaccines prepared with the 26th, 28th and 31th passage of BRD Ⅱ strain respectively. The HI antibody positive conversion rates of the children 42 days after being immunized with the 3 lots were 98.0%, 96. 8% and 96. 4%respectively, and the GMTs of them were 115. 1, 100.9 and 94. 8 respectively. The result showed good immunogenicity of BRDⅡ strain. The GMTs were decreased from year to year. They were 34. 4, 36. 9 and 31. 2 respectively at the 3rd year after immunization. However, no significant difference was found among the GMTs of the 3 lots. At the 3rd year,the antibody positive rates of the vaccines prepared with the 26th and 28th passage of BRD Ⅱ strain were still above 95%, but that of the vaccine prepared with the 31th passage was decreased to 89. 2 %, that was signficantly lower than those of the other 2 lots.