A 12-year cohort study on the efficacy of plasma-derived hepatitis B vaccine in rural newborns

摘要

AIM: To understand the anti-HBs persistence and the long-term preventive efficacy in rural newborns after vaccination with plasma-derived hepatitis B vaccine.METHODS: In the time of expanded program on immunization (EPI), the newborns were vaccinated with 10 μg × 3 doses of hepatitis B vaccine and 762 newborns who were HBsAg negative after primary immunization were selected for cohort observation from 1986 to 1998. Their serum samples were detected qualitatively and quantitatively for hepatitis B infecting markers, including HBsAg, anti-HBs and anti-HBc by SPRIA Kits. The annual HBsAg positive conversion rate was counted by life-table method.RESULTS: ① The anti-HBs positive rate was 94.44% for the babies born to HBsAg negative mothers and 84.21% for those born to HBsAg positive mothers in the 1^st year after immunization, and dropped to 51.31% and 52.50% in the 12^th year respectively. GMT value was dropped from 31.62 to 3.13 and 23.99 to 3.65 in the 2^nd to the 12^th year respectively. There was a marked drop in GMT at the 3^rd to the 5^th year, and in anti-HBs positive rate at the 9^th to the 10^th year. ② In the period of 12 years observation, the person-year HBsAg positive conversion rates were 0.12% (5/4150.0) in newborns born to HBsAg negative mothers and 0.20% (1/508.0) in those born to HBsAg positive mothers, and none of the HBsAg positive converted children became HBsAg chronic carriers. Compared with the baseline before immunization, the protective rates were 97.19% and 95.32% respectively.CONCLUSION: The protective efficacy of plasma-derived hepatitis B vaccine persisted at least 12 years, and a booster dose seems not necessary within at least 12 years after the primary three-doses immunization to newborns born to HBsAg negative mothers.