Two-dose Primary Vaccination With Either GSK Biologicals' 10-valent Pneumococcal Vaccine (Synflorix™) or Pfizer's Prevenar 13™ or Both Vaccines Followed by a Booster Dose of Synflorix™

The primary aim of this study is to assess the reactogenicity of Synflorix vaccine and
Prevenar 13 vaccine after primary vaccination at 2 and 4 months of age with either Synflorix
or Prevenar 13 vaccine or Prevenar 13 and Synflorix, respectively. In addition, this study
aims at assessing the safety, reactogenicity, immunogenicity and antibody persistence
(approximately 8-11 months following primary vaccination) of the Synflorix vaccine and
Prevenar 13 vaccine after primary vaccination at 2 and 4 months of age with either Synflorix
or Prevenar 13 vaccine or Prevenar 13 and Synflorix, respectively. This study also aims at
assessing the safety, reactogenicity and immunogenicity of the Synflorix vaccine when given
as a booster dose at 12-15 months of age following primary vaccination at 2 and 4 months of
age with either Synflorix vaccine or Prevenar 13 vaccine or Prevenar 13 and Synflorix
respectively.