Long-term antibody persistence in children primed and boosted with a DTPw-HBV vaccine at 2, 4, 6, 18, months of age

This paper presents 7- and 10-year follow-up immunogenicity data from two studies, which explored long-term persistence induced by combined tetravalent DTPw-HBV vaccines. The 10-year follow-up study compared two identical antigen-content, but different formulations of DTPw-HBV vaccine (adsorbed on either Al(OH)(3) or Al(PO(4)), whilst the 7-year follow-up study compared two different formulations of DTPw-HBV vaccines containing 5 and 10 microg of hepatitis B surface antigen (HBsAg), following a birth dose of HBV. Primary vaccination took place at 2, 4, 6 months and booster dosing at 18 months. A booster dose of local DTPw vaccine was given at 4 years of age to all returning subjects. At the end of the 7-year study, 90.9% subjects receiving 10 microg HBsAg had anti-HBs antibody concentrations > or =10mIU/ml; the majority of subjects remained seroprotected against diphtheria and tetanus (> or =90.9 and 100%, respectively) and 100% had seropositive levels for pertussis antigens. At the end of the 10-year follow-up study, > or =60.9% subjects had seroprotective concentrations of anti-HBs antibodies; > or =95.2 and 100% subjects were seroprotected against diphtheria and tetanus, respectively; > or =78.3% subjects were seropositive for pertussis. The results demonstrate long-term antibody persistence induced by combined DTPw-HBV vaccine.