On Oct. 2, 1996, the Food and Drug Administration (FDA) licensed a combined Hib conjugate and hepatitis B (recombinant) vaccine (COMVAX) for infants. Since 1991, the antigenic components of COMVAX have been used routinely in separate vaccines and have contributed to the declining incidence of infant Hib disease and hepatitis B virus (HBV) infection in the United States.

COMVAX was made of the antigenic components used in PedvaxHIB{Registered} and RECOMBIVAX HB  manufactured and distributed by Merck  (West Point, Pennsylvania).  COMVAX was indicated for vaccination against invasive Hib disease and HBV infection in infants born to HBsAg-negative women. Three doses of COMVAX TM should be administered at ages 2, 4, and 12-15 months. This vaccine must not be administered to infants younger than age 6 weeks because of potential suppression of the immune response to PRP-OMPC with subsequent doses of COMVAX.