united states children two months of age were randomly assigned to two groups that received either the commercially available oral trivalent poliovirus vaccine ( opv ) or an injectable ( inactivated ) trivalent poliovirus vaccine ( ipv ) with a confirmed minimum d-antigen content of 27 , 3.5 , and 29 units for poliovirus types 1 , 2 , and 3 , respectively .
C0032375
oral
C0032374
poliovirus vaccine