Dataset from Phase IIIb Study to Evaluate Immunogenicity, Antibody Persistency and Reactogenicity of DTPa - INFANRIX and dTpa - BOOSTRIX Vaccines Administered to Healthy Children Previously Primed With 3 Doses of DTPa Vaccine Compared to Placebo (HAVRIX®JUNIOR)

To evaluate the immunogenicity, persistence of antibodies and reactogenicity of GSK Biologicals' DTPa (INFANRIX) and dTpa (BOOSTRIX), when administered to subjects 18-20 months old, compared with not giving a booster DTP vaccine at 18-20 months. Study double blinded for the two DTP vaccines and single blinded for the control arm.