Dataset from To Assess the Safety, Reactogenicity & Immunogenicity of a 4th Dose of GSK Biologicals' Pneumococcal Vaccine or Prevenar™ in Children (12-18 Months) Previously Vaccinated in the Primary Study 105553 With Either Pneumococcal Vaccine or Prevenar™

This study will evaluate the safety, reactogenicity and immunogenicity of a booster dose of GSK Biologicals' pneumococcal conjugate vaccine compared to Prevenar™ given at 12-18 mo of age to children primed with either pneumococcal vaccine or Prevenar™ in study 105553. Antibody persistence will be evaluated at 8-14 mo after completion of the 3-dose immunization course in study 105553. The immune response to a booster dose of GSK Biologicals' pneumococcal conjugate vaccine will also be evaluated when given at 12-18 mo to subjects not primed with GSK Biologicals' vaccine but with Prevenar™. The study has 3 groups. 1 group of children primed with GSK Biologicals' pneumococcal conjugate vaccine will receive a booster dose of the same vaccine. 2nd group of children primed with Prevenar™ will receive a booster dose of Prevenar™ (control group). 3rd group of children primed with Prevenar™ will receive a booster dose of GSK Biologicals' pneumococcal conjugate vaccine. All children will receive concomitantly a booster dose of DTPa-HBV-IPV/Hib vaccine.