The following drug information is obtained from various newswires, published
medical journal articles, and medical conference presentations.
Diphtheria, Tetanus, Acellular Pertussis , Hepatitis B, Polio
Pediarix [Diphtheria and Tetanus Toxoids and Acellular Pertussis
Adsorbed, Hepatitis B (Recombinant) and Inactivated Poliovirus
Vaccine Combined] is a noninfectious, sterile, multivalent
pediatric vaccine for intramuscular administration.
The primary immunization series for Pediarix is 3 doses of 0.5
mL, given intramuscularly, at 6- to 8-week intervals (preferably 8
weeks). The customary age for the first dose is 2 months of age,
but it may be given starting at 6 weeks of age. Pediarix should not
be administered to any infant before the age of 6 weeks.
Approval of Pediarix was based on 12 clinical trials worldwide,
in which 20,739 doses of vaccine were administered to 7,028
In a double blind study conducted at 5 sites in the U.S., 484
infants were randomized into 4 groups to receive 3 different new
production lots or 1 earlier production lot of Pediarix vaccine. In
the 482 infants assessable for reactogenicity, rates of local
injection site reactions, restlessness, and fever did not increase
over the 3-dose primary series. Severe adverse reactions (grade 3),
defined as events that would prevent normal daily activity or in
the case of redness or swelling > 20 mm area and a rectal
temperature >103.1°F, occurred at rates of 3.4% or less.
In an open, randomized study conducted in the U.S., the
immunogenicity of Pediarix was compared with that of Infanrix and
Engerix-B. Immunogenicity was analyzed 1 month after the third
vaccine dose. One month after the third dose of Pediarix, vaccine
response rates to each antigen, with the exception of FHA, were
similar to the rates of separately administered vaccines. The
immune responses for each antigen contained in Pediarix were
considered similar to the comparator group if there was no more
than a 10% difference in vaccine response (pertussis antigens) or
seroprotection rates (diphtheria, tetanus, hepatitis B, and
poliovirus) between the 2 groups. The vaccine response to FHA
slightly exceeded the 10% limit for the difference between the
groups. The anti-FHA response in the Pediarix group in this study
was higher than the anti-FHA response observed in both studies that
demonstrated the clinical efficacy of Infanrix.
Adverse events associated with the use of Pediatrix may include
(but are not limited to) the following:
- Injection site reactions (pain, redness, or swelling)
- Loss of appetite
Mechanism of Action
The diphtheria toxin is produced by growing Corynebacterium
diphtheriae in Fenton medium containing a bovine extract. Tetanus
toxin is produced by growing Clostridium tetani in a modified
Latham medium derived from bovine casein. Both toxins are
detoxified with formaldehyde, concentrated by ultrafiltration, and
purified by precipitation, dialysis, and sterile filtration.
The 3 acellular pertussis antigens (PT, FHA, and pertactin) are
isolated from Bordetella pertussis culture grown in modified
Stainer-Scholte liquid medium. The antigens are purified in
successive chromatographic and precipitation steps. PT is
detoxified using glutaraldehyde and formaldehyde. FHA and pertactin
are treated with formaldehyde.
The hepatitis B surface antigen (HBsAg) is obtained by culturing
genetically engineered Saccharomyces cerevisiae cells, which carry
the surface antigen gene of the hepatitis B virus, in synthetic
medium. The surface antigen expressed in the S. cerevisiae cells is
purified by several physiochemical steps, which include
precipitation, ion exchange chromatography, and
The inactivated poliovirus component of Pediatrix is an enhanced
potency component. Each of the 3 strains of poliovirus is
individually grown in VERO cells, a continuous line of monkey
kidney cells, cultivated on microcarriers.
The efficacy of Pediatrix is based on the immunogenicity of the
individual antigens compared to licensed vaccines.
1.Centers for Disease Control. Diphtheria,
tetanus, and pertussis: Recommendations for vaccine use and other
preventive measures. Recommendations of the Immunization Practices
Advisory Committee (ACIP). MMWR 1991;40(RR-10):1-28.
2. Centers for Disease Control and Prevention.
Diphtheria. In: Atkinson W and Wolfe C, eds. Epidemiology and
prevention of vaccine-preventable diseases. 7th ed. Atlanta,
GA: Public Health Foundation; 2002:39-48.
3. Bisgard KM, Hardy I, Popovic T, et al.
Respiratory diphtheria in the United States, 1980 through 1995.
Am J Public Health 1998;88(5):787-791.