Evaluate lot-to-lot consistency, safety and reactogenicity of 3 doses of GSK Biologicals' 10-valent pneumococcal conjugate vaccine and non-inferiority with respect to Prevenar.

Test groups: 4 (400 subjects/group). 3 groups receiving 10-valent pneumococcal conjugate vaccine (3 different lots) as follows: - 10-valent vaccine (lot 1, 2 or 3) + DTPa combined vaccine; Control group receiving Prevenar + DTPa combined vaccine

Inclusion criteria:

• Male or female between, and including, 6 and 12 weeks (42-90 days) of age at the time of the first vaccination, free of obvious health problems and with written informed consent obtained from the parent/guardian of the subject.

Exclusion criteria:

• Use of any investigational or non-registered drug or vaccine other than the study vaccine within 30 days preceeding the first dose of study vaccine, or planned use during the study period.
• Planned administration/ administration of a licensed vaccine not foreseen by the study protocol during the period starting from one month before the first dose of vaccine(s) and during the entire study period.

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