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 TM is made of the antigenic components used in PedvaxHIB{Registered} and RECOMBIVAX HB{Registered} manufactured and distributed by Merck & Co., Inc. (West Point, Pennsylvania). Each 0.5-mL dose of COMVAX TM contains 7.5 ug of Haemophilus influenzae type b polyribosylribitol phosphate (PRP), 125 ug of Neisseria meningitidis outer membrane protein complex (OMPC) and 5 ug of hepatitis B surface antigen (HBsAg) with an aluminum hydroxide adjuvant and pH stabilizer in normal saline. Indications and Usage

COMVAX TM is 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 TM.

For complete protection against invasive Hib disease, infants should receive their first dose of Hib conjugate vaccine at age 2 months and should complete the full series by age 12-15 months (1). If the series is started late, the required number of doses of a vaccine containing PRP-OMPC (i.e., COMVAX TM or PedvaxHIB{Registered}) depends on the child’s age — three if started at age less than or equal to 10 months, two if started at age 11-14 months, and one if started at age 15-71 months. However, three doses of hepatitis B vaccine are required regardless of the child’s age when the series is started. Children who receive one dose of hepatitis B vaccine at or shortly after birth may be administered COMVAX TM at ages 2, 4, and 12-15 months.

The use of COMVAX TM has not yet been studied in infants born to women who are HBsAg-positive or women of unknown HBsAg status. However, there has been no evidence of diminished effectiveness of postexposure prophylaxis in populations that have received the initial doses of hepatitis B immune globulin and hepatitis B vaccine at birth followed by PedvaxHIB{Registered} and RECOMBIVAX HB{Registered} vaccines at 6-10 weeks of age and subsequently completed each vaccine series (CDC, unpublished data, 1994). Safety and Immunogenicity