Evaluation on booster immunization efficacy of 10 μg recombinant hepatitis B vaccine made by recombinant Deoxyribonucleic Acid Techniques in Hansenula Polymorpha Yeast by different dosage in children

Objective To analyze the efficacy of booster immunization with 10 g hepatitis B vaccine made by recombinant deoxyribonucleic acid(DNA)techniques in Hansenula Polymorpha Yeast (HepB-HPY) by different dosage. Methods Totally 1981 children aged over 5 years were selected, who completed the basic immunization of hepatitis B vaccine at birth, the blood plasma specimens of all sampled children were detected for hepatitis B virus (HBV) surface antigen (HBsAg), antibody to hepatitis B virus surface antigen (Anti-HBs) and antibody to hepatitis B virus core antigen (Anti-HBc) by chemiluminescence assay. Then, they were classified into Anti-HBs positive group and negative groups The children in positive group were immunized with one dose of 10 g HepB-HPY, while those in negative group were immunized with three doses of 10 g HepB-HPY. Their blood samples were collected after 1 month to detected Anti-HBs. Results The Anti-HBs positive rates were 38.62%, 95.66% and 99.75% respectively before booster immunization, after booster immunization with one dosage and after booster immunization with three dosages, the difference was statistical significant (2=73.794-1736.113, all P0.05). For the negative group, the Anti-HBs positive conversion rate after booster immunization with one dosage and three dosages were 92.93% and 99.67% respectively, the significant difference was observed (2=77.582, P0.05), while the Geometric Mean Concentration (GMC) of Anti-HBs negative children immunized with one dosage and three dosages were 783.23 mIU/ml and 2463.97 mIU/ml respectively, there was statistical significant difference (t=-14.201, P0.05). Compared with the children with Anti-HBs titers of0-1 mIU/ml before booster immunization, the positive conversion rate and GMC were significantly higher in those with the titers of 1-10 mIU/ml after booster immunization (all P0.05). Conclusion It is suitable to use 10 g HepB-HPY in Anti-HBs negative children aged between 5 and 8 years for one dose booster immunization,and in Anti-HBs negative children aged over 9 years for three dose booster immunization.