规范化甲肝减毒活疫苗(LA-1株)大规模免疫近期效果观察

Evaluation of Effectiveness of Large scale Immunization with a Live Attenuated Hepatitis A Vaccine(the LA 1 Strain)

为研究国产规范化甲肝减毒活疫苗（ＬＡ－１株）大规模免疫的安个性、免疫原性和保护效果，对广西８个县（市）１．５～１０岁儿童１７１６３４人随机分成疫苗接种组（９７２７８人）和对照组（７４３５６人）。疫苗组接种１针国产甲肝减毒活疫苗（ＬＡ－１株），滴度１０６．７５ＴＣＩＤ５０）。结果甲肝疫苗接种者均无局部和全身不良反应。免前阴性的疫苗组儿童于免后３、６、１２个月定人采血，用Ａｂｂｏｔ公司的ＩＭｘｍＥＩＡ试剂检测甲肝抗体阳性率分别为７３．９％（８８／１１９）、８３．２％（７９／９５）和８１．７％（４９／６０），ＧＭＴ分别为１２２．７、８０．７和８３．６ｍＩＵ／ｍｌ。随访９～１３个月，对照组发现１８例临床甲型肝炎病例，发病率２４．２／１０万，疫苗组无一病例发生，保护率１００％，保护率９５％可信限下限为８６．２％。

To evaluate the safety,immunogenicity and protectivity of Large-scale Immunization with the LA 1 strain,a live attenuated HAV vaccine, a randomised controlled double blind study was conducted among 171634 people between 1.5 and 10 years of age from 8 countise in Guangxi province (97278 in vaccine group and 74356 in control group).Vaccine group received one single dose of HAV vaccine of 10 6 75 TCID 50 .Those susceptibles with negative anti-HAV were bled at 3,6 and 12 months after the vaccination and blood test for anti-HAV using HAVAB supplied by IMx kit(Abbott Lab.)No. local or general reaction were reported in any of the vaccinates.Anti-HAV was detectable in 73.9%(88/119)、83 2%(79/95)and 81 7%(49/60) and the geometric mean titres were 122 7,80 7 and 83 6mIU/ml at 3,6 and 12 months after the vaccination respectively.During a follow up of 9 to 13 months, 18 cases of symptomatic HAV infection were found in the control group.An estimated vaccine efficacy was 100% with the 95% lower confidence limits (LCL) of 86 2%.