This randomised outcome assessor , blinded controlled trial will recruit 425 infants between 28 and 38days of age and randomly allocate them ( 1:1:1 ) to one of three pneumococcal conjugate vaccine ( PCV ) schedules : Synflorix at 2 , 4 , 6months of age , Prevenar13 at 2 , 4 and 6months of age , or an investigational schedule of Synflorix at 1 , 2 and 4months plus Prevenar13 at 6months of age .