This study will evaluate the safety, reactogenicity and immunogenicity of a booster dose of the pneumococcal conjugate vaccine, co-admin with a 1st dose or a 2nd dose of MMRV vaccine at 12-14 or respectively 14-16 months of age in children primed with the pneumococcal conjugate vaccine in study 105553. Antibody persistence will be evaluated at 8-10 months after completion of the 3-dose immunization course in study 105553. The immunogenicity, safety and reactogenicity of the 1st and 2nd dose of MMRV vaccine will also be evaluated when co-admin with the pneumococcal conjugate vaccine between 12-16 months of age.

The study has 3 groups.

• The 1st group will receive the booster dose of pneumococcal conjugate vaccine + 1st dose of MMRV vaccine at 12-14 mo of age and the booster dose of Infanrix hexa™+ 2nd dose of MMRV vaccine at 14-16 mo of age.
• The 2nd group will receive the booster dose of Infanrix hexa™ + 1st dose of MMRV vaccine at 12-14 mo of age and the booster dose of pneumococcal conjugate vaccine + 2nd dose of MMRV vaccine at 14-16 mo of age.
• The 3rd group will receive the booster dose of pneumococcal conjugate vaccine + the booster dose of Infanrix hexa™ at 12-14 mo. Subjects will be offered one dose of Priorix™ and Varilrix™ at 14-16 mo of age, outside the study.

Inclusion Criteria:

• a healthy male or female, 12-14 months of age at the time of first vaccination, who received at least one dose of pneumococcal conjugate vaccine during study 105553 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 preceding the vaccination, or planned use during the entire study period (active phase and safety follow-up).
• Planned administration/ administration of a vaccine not foreseen by the study protocol during the period starting one month before the first dose of vaccine(s) and ending 42-56 days after the last dose of vaccine(s).
• Administration of any additional pneumococcal vaccine since end of study 105553.
• Previous vaccination against measles, mumps, rubella and/or varicella. History of, or intercurrent measles, mumps, rubella and/or varicella/zoster diseases.
• Known exposure to measles, mumps, rubella and/or varicella/zoster within 30 days prior to study start.
• Immunosuppressive or immunodeficient condition.
• A history of seizures or neurological disease.

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