甲型肝炎减毒活疫苗加强免疫的效果

目的　观察国产甲肝减毒活疫苗不同免疫程序的加强免疫效果 ,以探求适宜的甲肝减毒活疫苗加强免疫程序。方法　在河北省正定县对 1～ 7岁的儿童采血检测抗 -HAV ,筛选甲肝易感者 ,按出生月份的单双数随机分为疫苗组和对照组 ,疫苗组接种 1针 ,观察免疫效果。在 1针法的基础上 ,随机抽取部分观察对象 ,分别按0、12月和 0、2、6月程序进行加强免疫 ,并于免疫后 1、2、3、6、7、12、13和 2 4个月采血清 ,观察免疫后的抗体动态。结果　接种 1针疫苗后 2～ 3个月抗体阳转率和几何平均效价均达高峰 ,分别为 92 .2 %～ 94 .9%和 12 6 .2～ 131.3mIU/ml,以后开始下降 ,12个月时降至 79.8%和 79.6mIU/ml。加强免疫后 ,抗体阳转率均达 10 0 % ,抗体水平成倍上升 ,其中以 0、12月程序免疫后抗体几何均值最高 ,为 32 94 .5mIU/ml。结论　甲型肝炎减毒疫苗具有良好的免疫记忆反应 ,采用 0、12月程序免疫效果更佳

Effect of Booster Immunization of Live Attenuated Hepatitis A Vaccine

Objective To observe the effects of booster immunization of live attenuated hepatitis A vaccine given at different schedules and explore an optimal immune schedule.Methods The blood samples were collected from the children aged 1 7 years in Zhengding County,Hebei Province,and detected for anti HAV.A total of 3515 susceptible children were selected and divided into vaccination and blank control groups randomly,according to the months when they were born.The children in vaccination group were injected with one dose (primary immunization) of live attenuated HA vaccine,and the immune effects of them were observed.On the basis of this,a proportion of the children were randomly selected and given one booster at the 12 th month,or 2 boosters at the 2 nd and 6 th month after the primary immunization respectively.The antibody dynamics were observed 1,2,3,6,7,12,13 and 24 months after the primary immunization respectively.Results Both positive conversion rate(94.9%) and GMT(131.3mIU/ml) of HA antibody reached peak values 3 months after the primary immunization.However,they decreased to 79.8% and 79.6mIU/ml respectively 12 months after the primary immunization.After the boosters were given,antibody positive rate reached 100%,and antibody level increased doubly.The GMT of antibody induced by a booster given at the 12 th month after the primary immuniztion was the highest (3294.5mIU/ml).Conclusion Live attenuated HA vaccine showed good immunological memory and was suitable for vaccination at a schedule of 0,12 month.