Ask the Experts - Which DTaP Product Is Most Efficacious?
Ask the Experts - Which DTaP Product Is Most Efficacious?
I'm responsible for the purchase of vaccines for a large pediatric group. Our contract for the DTaP product is now up for renewal. I have 2 questions related to the vaccine choices. Are there differences in efficacy for the DtaP vaccines? Will a combined DTaP-Hib vaccine for the primary series be available soon?
K. Perrin, MD
There are currently 4 acellular pertussis-combined vaccines (DTaP) licensed in the United States for the primary immunization series and an additional combination vaccine (DTaP-Hib) approved by the FDA for the fourth dose after 3 doses of DTaP have been given. All of the acellular pertussis vaccines contain 1 or more immunogens derived from Bordetella pertussis organisms. These antigens include detoxified pertussis toxin (ie, pertussis toxoid or PT, also termed lymphocytosis-promoting factor), filamentous hemagglutinin, fimbrial proteins (agglutinogens), and pertactin. All contain PT but only 2 contain pertactin (ACEL-IMMUNE and Infanrix), which is thought to be an important antigen for inclusion and ultimate protection. One vaccine -- Infanrix -- is thimerosal free.
Although licensed vaccines differ in their formulation of pertussis antigens, their efficacy appears similar. Detailed information on the various products, including efficacy, adverse events, and vaccine composition, are summarized in statements published by the American Academy of Pediatrics and the Centers for Disease Control and Prevention (CDC).
To answer your specific question, no single DTaP product can be recommended over another as far as efficacy is concerned. Most pediatricians are choosing the product that is least expensive.
Although the various acellular pertussis vaccines may be interchangeable, when feasible the AAP recommends using the same product for the first three doses for pertussis immunization. We simply do not have data on efficacy when we interchange vaccines during the primary series. When the type of DTaP product received previously is not known or the previous product is not readily available, any of the DTaP vaccines licensed for use in the primary series may be used. For the fourth and fifth doses, any licensed product is acceptable irrespective of prior vaccines received.
Although a combination DTaP-Hib vaccine is being investigated for the primary series, it appears that the antibody produced against Hib is lower in this combination product, which might potentially jeopardize protection against invasive Haemophilus influenzae type B disease. The FDA has therefore not approved a product combination to date for the primary series. The surrogate marker for approving any Hib vaccine is that 80% of recipients of the primary series achieve an antibody concentration of 1.0 mcg/mL or greater. This simply has not been feasible for the DTaP-Hib combination products that have been investigated. I would therefore not anticipate resolution of this problem in the near future and would purchase usual quantities of DTaP as is the practice for your group.
I'm responsible for the purchase of vaccines for a large pediatric group. Our contract for the DTaP product is now up for renewal. I have 2 questions related to the vaccine choices. Are there differences in efficacy for the DtaP vaccines? Will a combined DTaP-Hib vaccine for the primary series be available soon?
K. Perrin, MD
There are currently 4 acellular pertussis-combined vaccines (DTaP) licensed in the United States for the primary immunization series and an additional combination vaccine (DTaP-Hib) approved by the FDA for the fourth dose after 3 doses of DTaP have been given. All of the acellular pertussis vaccines contain 1 or more immunogens derived from Bordetella pertussis organisms. These antigens include detoxified pertussis toxin (ie, pertussis toxoid or PT, also termed lymphocytosis-promoting factor), filamentous hemagglutinin, fimbrial proteins (agglutinogens), and pertactin. All contain PT but only 2 contain pertactin (ACEL-IMMUNE and Infanrix), which is thought to be an important antigen for inclusion and ultimate protection. One vaccine -- Infanrix -- is thimerosal free.
Although licensed vaccines differ in their formulation of pertussis antigens, their efficacy appears similar. Detailed information on the various products, including efficacy, adverse events, and vaccine composition, are summarized in statements published by the American Academy of Pediatrics and the Centers for Disease Control and Prevention (CDC).
To answer your specific question, no single DTaP product can be recommended over another as far as efficacy is concerned. Most pediatricians are choosing the product that is least expensive.
Although the various acellular pertussis vaccines may be interchangeable, when feasible the AAP recommends using the same product for the first three doses for pertussis immunization. We simply do not have data on efficacy when we interchange vaccines during the primary series. When the type of DTaP product received previously is not known or the previous product is not readily available, any of the DTaP vaccines licensed for use in the primary series may be used. For the fourth and fifth doses, any licensed product is acceptable irrespective of prior vaccines received.
Although a combination DTaP-Hib vaccine is being investigated for the primary series, it appears that the antibody produced against Hib is lower in this combination product, which might potentially jeopardize protection against invasive Haemophilus influenzae type B disease. The FDA has therefore not approved a product combination to date for the primary series. The surrogate marker for approving any Hib vaccine is that 80% of recipients of the primary series achieve an antibody concentration of 1.0 mcg/mL or greater. This simply has not been feasible for the DTaP-Hib combination products that have been investigated. I would therefore not anticipate resolution of this problem in the near future and would purchase usual quantities of DTaP as is the practice for your group.
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