In this phase II , multicenter , observer-blind study ( www.clinicaltrials.gov : NCT00985751 ) conducted in the Czech Republic , toddlers ( 12-23 months ) were randomized ( 1:1:1:1:1 ) to receive one of four investigational vaccine formulations ( 10 or 30g each of dPly and PhtD , alone or in combination with polysaccharide conjugates from the pneumococcal non-typeable Haemophilus influenzae protein-D conjugate vaccine [ PHiD-CV ] ) , or the licensed PHiD-CV , in a 2-dose primary series plus booster at study months 0 , 2 and 6 .