Dataset from Immunogenicity and Reactogenicity Study of a New Formulation of GSK Biologicals' DTPa-HBV-IPV/Hib Vaccine Administered as a Booster Dose to 18-23 Months Old Children

The new formulation administered as a 4th consecutive dose will be compared to the current formulation of the vaccine in this partially double blind study. The study will be double-blind with respect to the two DTPa-HBV-IPV/Hib groups. The study will be open with respect to the DTPa-HBV-IPV group.