北京市儿童乙型肝炎疫苗接种12年后免疫效果观察

目的评价北京市儿童乙型肝炎(乙肝)疫苗接种12年后的免疫效果。方法2003年1至3月采取多阶段整群系统抽样方法在1991至2000年出生后接种乙肝疫苗的儿童中抽取2491人，用固相放射免疫法检测血清HBsAg、抗-HBs和抗-HBc水平，并对免疫后HBsAg阳性的原因进行分析。结果2491名3—12岁儿童中HBsAg阳性率为0．52％，疫苗免疫保护率为88．45％(95％CI为65．67％-97．89％)，抗-HBc阳性率为2．21％，各年龄组比较差异无统计学意义。接种重组(酵母)疫苗的3—6岁儿童，其抗-HBs平均阳性率为38．79％，但随年龄增大抗体阳性率明显下降；几何平均滴度为52．83mlU／ml，各年龄组比较差异无统计学意义。接种乙肝血源性疫苗的6—12岁儿童，其抗-HBs平均阳性率为50．79％，几何平均滴度为61．51mlU／ml，各年龄组抗体阳性率和几何平均滴度比较差异均无统计学意义。在13例HBsAg阳性儿童中，约50％儿童的母亲为HBsAg阳性。结论北京市儿童乙肝疫苗接种计划实施12年后，免疫人群保护效果理想，HBsAg阳性率未随免疫时间延长而明显增加。目前尚不需进行加强免疫，但重组(酵母)疫苗接种后抗-HBs阳性率随年龄增长而显著下降，应加强血清学监测。儿童接种后成为HBsAg携带者的主要原因为母婴垂直传播。

Observation on effects of hepatitis B vaccine immunization for 12 years in children in Beijing

OBJECTIVE: To evaluate the long-term protective effects of hepatitis B vaccine after immunizing to the children for 12 years in Beijing. METHODS: The multiple stratified cluster sampling was used in this epidemiological survey. The sampling children's blood serum HBsAg, anti-HBs and anti-HBc were checked and measured by the solid phase radioimmunoassay (SPRIA). The serological level of these index and the causes of the children with HBsAg positive were analyzed. RESULTS: There were 2,419 cases 3-12 years-old children immunized with the hepatitis B vaccine in infant period were surveyed and the total HBsAg positive rate was 0.52%. The vaccine protective rate was 88.45% (95% CI: 65.67%-97.89%). The total anti-HBc positive rate was 2.21%, being no statistical significance among the age groups. The average anti-HBs positive rate of 3-6 years-old children immunized with gene recombining vaccine was 38.79% and descending greatly following the age's dropping. The geometric means of anti-HBs serological titer (GMT) was 52.83 mIU/ml, showing no statistical significance among the age groups. The average anti-HBs positive rate of 6-12 years-old children immunized with the blood rooting vaccine was 50.79%. The geometric means of anti-HBs serological titer (GMT) was 61.51 mIU/ml. There were no statistical significances among the age groups. Among the HBsAg positive children, more than 50% of the children's mothers were HBsAg positive also. CONCLUSIONS: The protective effects given by immunization were significant after the hepatitis B vaccine vaccination for 12 years in Beijing. The booster immunization was not necessary, because the HBsAg positive rate didn't ascend obviously as the immunization time prolonging. As the anti-HBs positive rate of children who were immunized by the gene recombining vaccine might be descending following the age's dropping greatly, we should strengthen the serological surveillance of hepatitis B. The main cause that the children became the HBsAg carrier should be a vertical transmission.