【摘要】 目的　观察不同剂量的甲型肝炎 (甲肝 )减毒活疫苗免疫原性与免疫持久性。方法　对河北省正定县 4个村 16 6名 6～ 8岁事先经血清检测抗 HAV阴性的易感儿童 ,按村分成 4组 ,分别给予 0 .5、1、2及 2剂经 6 0℃ 3h灭活处理的甲肝减毒活疫苗 (滴度为 10 6.52 TCID50 )。并于接种后 3、12、2 4、36及 48个月采集观察对象血清 ,采用Abbott IMxmEIA试剂检测血清抗 HAV。并对接种 1剂、2剂活疫苗组免后 4年部分血清检测中和抗体。结果　免后 3个月抗体阳转率、抗体几何平均滴度(GMT)同疫苗滴度呈剂量效应关系。免疫后各组抗体水平于免疫后 3个月达高峰后逐年下降 ,12个月内下降较明显 ,12个月后下降缓慢。免疫后 4年接种 2剂活疫苗组抗体阳性率与GMT均高于接种 0 .5剂及 1剂组。接种 1、2剂活疫苗组部分经Abbott IMxmEIA试剂检测抗 HAV阴性的血清检测中和抗体 ,其阳性率为 6 0 %及 83%。结论　甲型肝炎减毒活疫苗的免疫原性与免疫持久性同疫苗的滴度有关 ,滴度为 10 6.83 TCID50 的减毒活疫苗具有较理想的免疫原性及免疫持久性。减毒活疫苗接种后近期内不必予以加强免疫更多还原

【Abstract】 Objective This study was carried out to assess the long term persistence of antibodies against hepatitis A in different vaccine dosage groups. Methods One hundred and sixty six susceptibles aged form 6 to 8 years old were selected in Zhengding county, and were divided into 4 different dose groups. Each group received 10 6.17 TCID 50 , 10 6.52 TCID 50 , 10 6.83 TCID 50 of attenuated hepatitis A vaccine or 10 6.83 TCID 50 of the same vaccine but treated with 60℃ for 3 hours. All subjects were bled at month 3, 12, 24, 36 and 48. All serum specimens were tested for antibodies to HAV using Abbott IMx mEIA reagent. Part of the tested negative serum specimens were retested by neutralization assay for 10 6.52 TCID 50 and 10 6.83 TCID 50 doseage groups at 4 years after vaccination. Results The seroconversion rate and GMT 3 months after vaccination in each dosage group showed a significant dose response relationship. Antibody levels reached the peak at month 3 in each group but declined dramatically within one year and the decline slowed down thereafter. The serocoversion rate and GMT in 10 6.83 TCID 50 dose group 4 years after vaccination was significant higher than those of other dosage groups. Positive rates of neutralizing antibodies in B and C dosage group were 60.0 % and 83.3 % respectively. Conclusion The immunogenicity and long term persistence were related to the attenuated hepatitis A vaccine titer. The vaccine, whose titer was 10 6.83 TCID 50 , had good immunogenicty and long term persistence. Booster dose was not needed within short time after initial vaccination.更多还原