This study will assess the safety, reactogenicity, immunogenicity and persistence of two formulations of GSK Biologicals' pneumococcal vaccine 2189242A [high dose (HD) or low dose (LD)] given as a 3-dose primary vaccination course during the first 6 months of life followed by a booster dose at 12-15 months of age when co-administered with Infanrix hexa™ and compared to the vaccination with Synflorix™ and with Prevnar 13™ similarly co-administered with the Infanrix hexa™ vaccine.