An Evaluation on Effectiveness of Plasma-derived Hepatitis B Vaccine Immunization to Newborns after 14-years

In order to understand the anti-HBs persistence and the long-term preventive efficacy in newborns after vaccination with plasma-derived hepatitis B vaccine,a cohort observation was carried out in the following 1～14 years in Zhengding County,Hebei Province.The newborns were vaccinated with 10ug/ml×3 doses of hepatitis B vaccine,and 762 newborns who were HBsAg negative after primary immunization were selected for a cohort observation from 1986 to 1989.Their serum samples were detected qualitatively for hepatitis B infecting markers,including HBsAg,anti-HBs and anti-HBc by SPRIA Kits.The annual HBsAg positive seroconversion rate was counted by life-table method.The results showed that the anti-HBs positive rates were from 94.44% to 57.89% for babies born to HBsAg negative mothers and from 95.83% to 62.26% for babies born to HBsAg positive mothers at the 1 st to 9 th year,and still 50% or so at the 10 th to 14 th year.The person-year HBsAg positive seroconversion rate was 0.08%(6/7612.5),and none of the HBsAg positively converted children became HBsAg chronic carriers.Compared with the baseline(1.13%)before immunization,the protective rate was 92.92%.In conclusion,the protective efficacy of plasma-derived hepatitis B vaccine persisted at least 14 years,and a booster dose seems not necessary within at least 14 years after the primary three-doses immunization to newborns.