PR Newswire, 810 Seventh Avenue, New York, NY 10019 - Friday, 4 October 1996

Comvax combines liquid PedvaxHIB(R) (haemophilus b conjugate vaccine (meningococcal protein conjugate)) and Recombivax HBO (hepatitis B vaccine, (recombinant)), both vaccines currently marketed by Merck. It will be available in January, 1997. The Hib component of Comvax, PedvaxHIB is the only Hib vaccine indicated for a three dose regimen (two primary and one booster). All others require four doses. The hepatitis B component, RecombivaxHB, was the first genetically- engineered human vaccine to be licensed and has been widely used since its introduction in 1986.

Gordon Douglas, M.D., president, Merck Vaccine Division, in announcing the licensure of the vaccine, noted that it marks another important milestone for Merck, a leader in vaccine development. "Comvax is a step that can help physicians and parents simplify the complex 'alphabet soup' of childhood immunizations. Comvax compliments an immunization schedule that includes the use of acellular pertussis and injectable polio vaccines by keeping to a minimum the number of injections required," Dr. Douglas said.

Dr. Douglas pointed out that technologies associated with developing combination vaccines are complex. "This process is not straightforward and the scientific challenges are significant. We had to overcome, among other things, the potential for one of the components to interfere with the other, to assure that the two vaccines work as effectively in combination as they do alone," he said.

Comvax can be administered concomitantly with other standard pediatric vaccines including M-M-R 11 (measles, mumps, rubella), DTP (diphtheria, tetanus and pertussis) OPV (oral polio vaccine), and a booster dose of DTaP (diphtheria, tetanus and acellular pertussis) at 15 months of age. (Injectable vaccines should be administered using separate sites and syringes.) It has been shown to be generally well tolerated and highly immunogenic in infants 6 weeks to 15 months of age.

In combined trials involving 1216 healthy infants, safety and immenogenicity of Comvax were compared with those of the component vaccines, liquid PedvaxHIB and Recombivax HB, given concurrently. Antibody responses following the recommended three-dose regimen of Comvax were similar to those following concurrent administration of the monovalent vaccines administered according to the same schedule.

Adverse experiences were generally similar in type and frequency to those observed in infants who had received concurrent injections of liquid PedvaxHIB and RecombivaxHB at separate sites. These include soreness, erythema, and swelling at the site of injection, and some irritability, somnolence and crying. As with any vaccine, however, there is the possibility that broad use of Comvax could reveal adverse experiences not observed in clinical trials. Comvax is contraindicated in individuals with known hypersensitivity to any component of the vaccine.

Hib Most Frequent Cause of Bacterial Meningitis

Before the introduction of haemophilus b conjugate vaccines, haemophilus influenza type b bacteria (Hib) was the most frequent cause of bacterial meningitis and a leading cause of serious, systemic bacterial disease in young children worldwide. The disease typically occurred in children younger than five years of age, the peak incidence being between 6 and 11 months of age. Hib caused an estimated 20,000 infections annually in the U.S. approximately 12,000 of which were meningitis in young children.

The mortality rate for Hib meningitis is about 5 percent. Additionally, up to 35 percent of survivors develop permanent neurologic problems including seizures, deafness, and mental retardation. The same bacterium also causes cellulitis, epiglottitis, sepsis, pneumonia, septic arthritis, osteomyelitis and pericarditis.

Among children under the age of five, those in several groups are considered at risk for Hib infection. These include daycare attendees, those in lower socioeconomic groups, African-Americans, Native Americans, those in household contact with infected individuals, those with asplenia, sickle cell disease or antibody deficiency syndromes.

The Advisory Committee on Immunization Practices (ACIP) and the Committee on Infectious Diseases of the American Academy of Pediatrics (AAP) have endorsed infant immunization for the control of Hib beginning routinely at two months of age.

Hepatitis B Is A Serious Disease

According to the Federal Centers for Disease Control (CDC), the hepatitis B virus produces major health problems in the U.S. Its incidence has increased 37 percent from 1979 to 1989 and as many as 300,000 new infections occurred annually during the period 1980-1991.

There is no specific treatment for the disease and prognosis after infection is influenced by age. Infants who become infected by perinatal transmission have a 90 percent risk of chronic infection and up to 25 percent will die of chronic liver disease as adults. Those infected as infants or young children are more likely to be persistently infected and to develop serious chronic liver disease. The dose of virus to which the individual is exposed and the severity of any underlying disease also are important predictors of disease severity and outcome.

Worldwide, sexual contact and perinatal transmission have had the greatest impact on hepatitis B transmission. The virus is also spread by the parenteral route. While U.S. incidence was previously associated with exposure to blood or blood products, today, this is rare. More commonly, the virus is associated with use of illegal drugs and multiple sexual contacts. Transmission also is often associated with close interpersonal contact with an infected individual and with crowded living conditions.

The hepatitis B virus has been found in almost every body fluid, including tears, saliva, breast milk, urine, semen, synovial fluid and vaginal secretions. It can survive for days on environmental surfaces.

From 5 to 10 percent of older children and adults and up to 90 percent of infants become chronic carriers of hepatitis B. Experts estimate that more than 285 million people worldwide are persistently infected with hepatitis B virus. The CDC estimates there are at least 1 million chronic hepatitis B carriers in the U.S. who are potentially infectious to others.

The Advisory Committee on Immunization Practices (ACIP) and the Committee on Infectious Diseases of the American Academy of Pediatrics (AAP) have endorsed universal infant immunization for the control of hepatitis B infection.

Product Information

Comvax is intended for intramuscular injection. Infants should be vaccinated with a 3-dose series at approximately 2, 4, and 12 to 15 months of age, allowing a 2 month interval between the 2 initial doses.

Comvax, which contains no preservatives, is supplied in 0.5 mL single dose vials, each of which contains 7.5 mcg haemophilus b PRP and 5 mcg HBsAg. The product also is available in a box of 10 single dose vials.

It should be stored at 36-46 degrees F. The vaccine is manufactured at the Merck facility in West Point, Pa., and will be marketed by the Merck Vaccine Division. Pricing has not yet been announced. Continued...

Copyright (c) 1996/PR NewsWire. Reproduced with permission. Reproduction of this article (other than one copy for personal reference) must be cleared through the Permissions Desk, PR Newswire, 810 Seventh Avenue, New York, NY 10019.
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