新生儿乙型肝炎疫苗普遍接种的长期免疫效果

Long-term efficacy of infant hepatitis B immunization program

目的 观察新生儿乙型肝炎(简称乙肝)疫苗普遍接种预防儿童期乙型肝炎病毒(HBV)感染的长期免疫效果和对儿童乙肝发病的影响。 方法 1986年起在乙肝高发区隆安县实施不筛检母亲HBsAg、新生儿普遍接种常规剂量乙肝疫苗的免疫方案。采用出生队列定群随访、横断面调查和监测乙肝发病情况的方法对血源乙肝疫苗和重组酵母乙肝疫苗的保护效果进行观察。 结果 血源乙肝疫苗免疫后1～1 3年HBsAg阳性率为0.7％～2.9％,平均1.7％,保护率为83.5％～96.6％,HBV感染率为1.1％～5.1％,平均2.4％,保护率为93.5％～98.4％。重组酵母乙肝疫苗免疫儿童的HBsAg阳性率为1.8％～2.4％,平均2.0％,保护率为78.4％-85.2％。免疫实施14年后, 1～14岁人群乙肝发病率为1.5/10万,比历史对照同龄者减少了91.8％;未免疫儿童发病率为14.4/1 0万,与历史对照差异无显著性,免疫儿童中无乙肝病例发生,保护率为100％。 结论 新生儿乙肝疫苗免疫后13年内不必加强免疫,重组酵母乙肝疫苗与血源性乙肝疫苗的保护效果相似,乙肝疫苗预防作用已初见成效。

Objectives To evaluate the long-term efficacy of infant hepatitis B (HB) immunization program on preventing hepatitis B virus (HBV) infection, and to assess its impact on the incidence of HB in children. Methods Since 1986, the universal HB vaccination for newborn babies with standard, pediatric dose had been launched without serologic prescreening of pregnant women for HBsAg, in a high endemic county of Long-An. A hepatitis surveillance system was set up to evaluate the possible impact on the incidence of hepatitis B. To serologically evaluate the effectiveness of the program, a stratified random sampling of 1 000 children in 1987 birth cohorts, who received plasma-derived HB vaccine, was recruited for long-term follow up at the age of 1-13 years. A cross-sectional seroepidemiological survey was conducted in the county in 1985, before the program, and in 2001, for 1 551 children born in 1996-2000 who were administered yeast recombinant HB vaccine. Results During the 1-13 years after the program, the rates of HBsAg-positive were 0.7%-2.9% with an average of 1.7% and the protective rates were 83.5%-96.6%. HBV infection rates were 1.1%-5.1% with an average of 2.4% and the protective rates were 93.5%-98.4%. For the population aged 1-4 years who were immunized with recombinant HB vaccine, HBsAg positive rates were 1.8%-2.4% with an average of 2.0% and the protective rates were 78.4-85.2%. 14 years after the program, the cumulative incidence of acute hepatitis B in the children aged 1-14 years fell to 1.5 cases per 100 000 children, down 91.8% as compared with that in 1985-1987. However, the cumulative incidence of 14.4 cases per 100 000 population in unvaccinated children was not significantly different from that in the history controls. Acute hepatitis B children had not been reported, showing that the vaccination program was 100% protective in children. Conclusions The universal infant HB vaccination program in a hyperendemic area has proved to be effective in controlling HBV infection and decreasing the incidence of acute hepatitis B in children. Booster dose is unnecessary in 13 years after the immunization. The protective efficacy of yeast recombinant HB vaccine is similar to that of plasma-derived HB vaccine.