Immunogenicity and efficacy of a recombinant DNA hepatitis B vaccine, GenHevac B Pasteur in high risk neonates, school children and healthy adults

Abstract

The immunogenicity and the protective efficacy of a recombinant DNA hepatitis B vaccine, GenHevac B Pasteur with or without passive immunization with hepatitis B immunoglobulin (HBIG) in high risk neonates born from HBsAg and HBeAg positive mothers was evaluated. Twenty-six neonates (group A) received HBIG 100 IU intramuscularly at birth plus GenHevac B Pasteur 20 μg at birth, 1, 2 and 12 months of age while another 23 neonates (group B) received only GenHevac B Pasteur vaccine. Forty high risk newborns who received no immunization served as control group. It was found that at months 4, 12, 13 and 24 the seroconversion rate in both group A and B were very high in the range of 95-100% with the GMT ranging from 10-160,000 mIU/ml. In the control group of infants, 85% had HBsAg positive at one year of age but it was only 3.8% and 8.7% in vaccinated groups A and B, respectively. The protective efficacy in neonates group A and B were 95.5% and 89.8% at one year, respectively, with no statistically significant difference. In 46 normal school children (group C) and 48 healthy adults (group D) who received the same dose of GenHevac B Pasteur the seroconversion rates at month 4 after receiving 3 doses of vaccination were 97.8% and 83.3% in group C and group D, respectively. At month 12, the seroconversion rate in group C rose to 100% and was significantly higher than the 89.6% of group D. However, at month 13, after a booster dose at month 12, the seroconversion rate of group D also rose to 95.8%, close to the 100% of group C. The GMT of anti-HBs responses in school children were statistically significant higher than those of healthy adults at months 4, 6 and 12, but both groups showed similar anamnestic antibody responses after the booster dose at month 12 with a GMT of 27,800 mIU/ml and 12,520 mIU/ml in groups C and D, respectively. This full dose of GenHevac B Pasteur produces high immunogenicity and protective efficacy in high risk neonates as well as in school children and healthy adults. During the first year the seroconversion rate in healthy adults was lower than that of school children but finally caught up at month 13 with high GMT levels. It is concluded that full dose recombinant DNA hepatitis B vaccine alone is equally effective as the vaccine plus HBIG in prevention of vertical HBV transmission from HBeAg carrier mothers to their high risk neonates.