Immunogenicity of two different dosages (10 and 5 μg) of recombinant DNA hepatitis B vaccine in healthy neonates

The immunogenicity of a half (5 μg) and a full (10 μg) dosage of recombinant DNA yeast-derived hepatitis B vaccine (HB-Vax-DNA) in healthy neonates was assessed in order to compare two candidate dosages of vaccine. After randomization 174 newborns of HBsAg-negative mothers entered the study. Neonates received four doses of either 10 or 5 μg hepatitis B vaccine, according to the DTP polio immunization schedule at months 3, 4, 5 and 11. No serious adverse reactions were observed; 15.5% of vaccinated newborns suffered mild transient local symptoms. The vaccine was highly immunogenic irrespective of dosage of vaccine; all infants developed anti-HBs levels ⩾ 10 IUl−1, 99% ⩾ 100 IUl−1. A dosage of 10 μg hepatitis B vaccine produced higher antibody levels than 5 μg hepatitis B vaccine after primary vaccination (first three doses) but not after booster vaccination (fourth dose) (p = 0.06 and 0.75, respectively). Either vaccine dosage can be recommended for incorporation in the Expanded Programme on Immunization in the Netherlands