This study assessed the immunogenicity and safety of two vaccination regimens that employed either GSK Biologicals' combined DTPa-HBV-IPV/Hib vaccine or DTPa-IPV/Hib vaccine. In the two groups, infants received the DTPa-IPV/Hib vaccine at 3 and 4 months of age, as the first 2 doses of the primary vaccination course. At 5 months of age, they received either the DTPa-IPV/Hib vaccine co-administered with the HBV vaccine or a dose of the DTPa-HBV-IPV/Hib vaccine as a 3rd dose. Infants in the two groups had previously received 2 doses of HBV vaccine at birth and at 1 month of age.

Inclusion Criteria:

• A male or female infant at the age of 11 - 17 weeks.
• Written informed consent obtained from the parents or guardians of the subject.
• Free of obvious health problems as established by clinical examination before entering into the study.
• Hepatitis B vaccine at birth and one month of age.

Exclusion Criteria:

• Previous vaccination against measles, mumps, rubella and/or varicella.
• Use of any investigational or non-registered drug or vaccine other than the study vaccines within 30 days preceding the first dose of study vaccine, or planned use during the study period.
• A family history of congenital or hereditary immunodeficiency.
• Any confirmed or suspected immunosuppressive or immunodeficient condition, including HIV infection.
• Major congenital defects.
• History of allergic disease or reactions likely to be exacerbated by any component of the vaccine.

Patient-level data for this study will be made available through www.clinicalstudydatarequest.com following the timelines and process described on this site.