A phase III, randomised, open, controlled, multicentre, primary vaccination study to evaluate the immunogenicity and persistence of 1 and 2 doses of GlaxoSmithKline Biologicals’xx meningococcal conjugate vaccine MenACWX-TT in toddlers (after 1 month and up to 5 years) and to demonstrate noninferiority of co-administration of MenACWY-TT and Pfizer’xxs 13-valent pneumococcal conjugate vaccine Prevenar 13 versus separate administration of the 2 vaccines.