Observation on efficacy of yeast derived hepatitis B vaccines on vaccinated children in three years later

  Objective   To evaluate the immune efficacy and safety of yeast-derived hepatits Bvaccines(YDV)on children.

  Methods   One hundred and ten children aged 7 to 9 years old were randomly selected at some schools in Beipiao city, Liaoning Province, whose HBsAg, anti-HBs, anti-HBc were all negtive.They were vaccinated with YDV.Test serum anti-HBs at 3, 7, 12, 24 and 36 months after the first dose YDV was vaccinated.

  Results   Positive seroco nvertion rates of antiHBs were 75.7%, 100.0%, 95.1%, 90.7% and 87.5%, respectively; positive seroconvertion rate of anti-HBs of the female was higher than that of the male(P < 0.05)at 24 month(T 24).Mean geometric titres(GMT)of anti-HBs wer 43.78, 402.92, 170.43, 155.49 and 107.57 mU/ml, respectively; The results indicated that GMT of anti-HBs reached its peak at 7 month(T7);the difference of the GMT of anti-HBs between the male and the female was not significant(P > 0.05); the distribution of anti-HBs titre was significantly different(P < 0.05)only at 12 month(T 12).

  Conclusion   YDVwas safety and immunogenic to vaccinate children.It was necessary to follow up these children to know how long the protective level could last.