Observational Study on Immunization Effectiveness of Hepatitis B Vaccine in Newborn Babies During 15 Years

Objective] In order to investigate the anti-HBs transformation tendeney and the long-term protective effect in children who has been immunized with hepatitis B vaccine at birth.[Methods] Since 1986, the 5006 children who were immunized with hepatitis B vaccine at birth and follow up at least once in each 1～2 year. Serum HBsAg、 anti-HBs and anti-HBc were tested.[Result] The results of all examinationes showed that HBsAg positive rate in the vaccine group were 0 63%～2 32% during 15 years. The HBsAg average positive rate was 1 38% and that was much lower than 10.33% of same age population of background survey. The protective rate was 86.65%(95% confidence interval:72.13%～100.00%). The highest peak of the anti-HBs positive rate and the geometric mean titres (G) both appeared in 7 th ～12 th month and then gradually decreased with the lapse of time. But the anti-HBs positive rate of 15 years old children was 45.31% and GMT was 27.95 mIu/ml. The HBaAg positive rate and the anti-HBc positive rate were not changed.[Conclusion] The efficacy of hepatitis B vaccine was long-term. The decrease of anti-HBs positive rate did not lead to increase of HBsAg positive rate. The results indicated that anti-HBs was a indirect indicator only, at time of booster dose was selected.