【摘要】 目的观察乙型肝炎疫苗接种后９年效果。方法对９年前经随机、双盲、有安慰剂对照严格设计的，曾完成疫苗全程接种的疫苗组１２６名、安慰剂组１３５名５～９岁儿童进行随访并采血，询问发病情况，检测乙型肝炎３项指标（ＨＢｓＡｇ、抗ＨＢｃ和抗ＨＢｓ）。对抗体下降原因进行多因素分析。结果经９年观察，失访率控制在４％～１９％。第九年（Ｔ１０８）疫苗组抗体阳性率和ＧＭＴ仍显著高于安慰剂组，分别为６５３％、５４７和２８２％、１４６。但与第六年（Ｔ７２）相比，疫苗组两指标均明显下降。对４、６、９年抗体下降原因做多因素分析均显示，Ｔ１２抗体滴度高低是抗体是否能持续存在的重要因素，自然加强可能也起一定作用。９年中，Ｔ１０８时安慰剂组发生１例临床乙型肝炎病人，疫苗组无病例；对ＨＢＶ感染的保护率为８１４％，对ＨＢｓＡｇ阳转的保护率为８４６％。与第六年相比基本相同。结论乙肝疫苗接种后９年效果仍是完好的，无需复种更多还原

【Abstract】 Objective To observe the effectiveness of hepatitis B vaccine nine years after primary immunization. Methods A randomized, controlled and doubleblinded trial was designed with 126 children primarily immunized with local produced plasmaderived hepatitis B vaccine nine years ago and 135 placebocontrol children aged five to nine years. All the children were followedup, their blood samples collected and their disease occurrence examined. Their hepatitis B surface antigen (HBsAg), antibody against hepatitis B core antigen (antiHBc) and antibody against hepatitis B surface antigen (antiHBs) were tested. Causes of lowering in their antibodies were analyzed with multivariate methods. Results During the nineyear followup, 4% to 19% of the study subjects dropped out. In the ninth year after immunization (T108), antiHBs positive rate in the vaccinees and their geometric mean titer (GMT) (65.3% and 5.47, respectively) were still significantly higher than those in the placebocontrols (28.3% and 1.46, respectively), but significantly lower than those in the 6th year after immunization (T72). Multivariate analysis for the causes of lowering in the antibody during the 4th, 6th and 9th year after immunization showed that antibody titer in the vaccines first year after immunization (T12) was a crucial factor for the persistence of the antibody, and natural booster might also played a certain role in it. In the T108, one clinical case of hepatitis B occurred in the placebo control group, but no cases in the vaccinees found, with a protection rate of 81.4% from HBV infection and 84.6% from HBsAg positivecoversion, similar to those in the T72. Conclusion The effectiveness of HB vaccine still existed nine years after primary immunization, and no booster dose was needed so far.更多还原