国产乙型肝炎血源疫苗免疫保护持久性及加强免疫△

目的确定国产乙肝血源疫苗低剂量免疫保护持久性及何时需要加强免疫。方法采用放射免疫（ＲＩＡ）法测定新生儿计划免疫７年后的血清学效果和加免实验的抗体反应。结果１０１８名乙肝免疫儿童的保护性抗体阳性率从免后１～２年的７５．０％下降为第７年的４８．２％,而ＨＢｓＡｇ和抗－ＨＢｃ阳性率却均始终处于低水平。１４４名免后６～７年且ＨＢｓＡｇ和抗－ＨＢｃ均阴性儿童,加免前抗－ＨＢｓＧＭＴ为１０．４ｍＩＵ／ｍｌ,抗－ＨＢｓ阳性率５４．９％;加免后１个月和１年,抗－ＨＢｓＧＭＴ分别为１９０．６和２５．３ｍＩＵ／ｍｌ,而抗－ＨＢｓ阳性率则分别为８９．６％和７５．５％。加免后１个月抗－ＨＢｓＧＭＴ和阳性率均显著高于加免前的水平（Ｐ＜０．０１）。但加免后１年时抗－ＨＢｓＧＭＴ又接近加免前水平,而阳性率仍显著高于加免前。６５名加免前抗－ＨＢｓ阴性儿童,加免后１个月有４０名儿童抗－ＨＢｓ≥１００ｍＩＵ／ｍｌ,提示乙肝疫苗免后抗体阴转者可能仍保持免疫记忆。结论国产乙肝血源疫苗低剂量免疫有很好的免疫保护持久性,初免后７年不必加强免疫。

Persistence of HB vaccine immune protection and response to hepatitis B booster immunization

OBJECTIVE: To determine the persistence of immune protection of China-made, plasma-derived HBV vaccine in infants and the time table of booster immunization. METHODS: Serological effect of 7-year follow-up study and antibody response of an experimental study on booster were detected using radioimmunoassay. RESULTS: The protective anti-HBs positive rates of 1,018 children, who were vaccinated according to the regimen of three doses of 10 micrograms HBV vaccine, declined from 75.0% during the first two years to 48.2% at 7 years after the first dosages, however, the positive rates for HBsAg and anti-HBc always fluctuated at low frequency. 144 children aged 6 or 7 years old, who received the HBV vaccine in their infancy and were negative for both HBsAg and anti-HBc before booster, were selected from 1,018 children of the follow-up study and boosted with 1 microgram (intradermally) or 2 micrograms (hypodemically) HBV vaccine. Their anti-HBs GMT and anti-HBs positive rate were 190.6 mIU/ml and 89.6% at one month after booster, significantly higher than 14.7 mIU/ml and 54.9% before booster (P < 0.01), and declined back to 25.3 mIU/ml and 75.5% at 12th month; among 65 children with the anti-HBs negative before booster, 40 of them had the level of anti-HBs > or = 100 mIU/ml one month after booster, suggesting the retention of immunological memory in most of them. CONCLUSIONS: No need for revaccination against hepatitis B at 7th year after the initial immunization due to better persistence of immune protection of the vaccine.