Diphtheria-tetanus-acellular pertussis vaccine adsorbed (Triacelluvax; DTaP3-CB): a review of its use in the prevention of Bordetella pertussis infection.

UNLABELLED: DTaP3-CB (Triacelluvax) is an acellular pertussis (aP) vaccine containing 3 antigens from purified Bordetella pertussis bacteria combined with diphtheria and tetanus toxoids (DT). In addition to purified filamentous haemagglutinin and pertactin, DTaP3-CB contains pertussis toxin which has been genetically rather than chemically detoxified. As shown in randomised, double-blind clinical trials in infants, DTaP3-CB elicits an immune response similar to or greater than that of whole cell (DTwP) vaccines. Results of a large multicentre study comparing DTaP3-CB with 12 acellular and 1 DTwP vaccine indicate that DTaP3-CB, like all acellular vaccines, induces variable immune responses to different pertussis antigens; however, antibody titres to pertussis toxin are normally higher after immunisation with the genetically detoxified vaccine than with other 3- or 4-component vaccines. When given as a fourth or fifth booster dose, DTaP3-CB produced a significant immune response in infants primed with 3 doses of either a DTaP or DTwP vaccine. Virtually all infants immunised with DTaP3-CB had a serological response to diphtheria and tetanus toxoids. Data from 2 very large efficacy studies indicate that DTaP3-CB has high and long lasting protective efficacy against culture-confirmed pertussis which is greater than that of a 2-component vaccine (DTaP2-SB) and the whole cell DTwP-CON vaccine after a 3-, 5- and 12-month immunisation schedule and after a 2-, 4- and 6-month schedule with the DTwP-CON vaccine. However, the DTwP-CON whole cell vaccine has been noted for its low immunogenicity in 1 study and low efficacy and immunogenicity in another study. On the other hand, DTaP3-CB vaccine has similar efficacy to DTaP3-SB (after immunisation at 2, 4 and 6 months), DTaP5-CON and DTwP-EVANS against culture-confirmed pertussis with > or =21 days cough in infants immunised according to a 3-, 5- and 12-month schedule. Infants immunised with DTaP3-CB experienced significantly fewer adverse events such as pain, redness, swelling and irritability than infants given DTwP. DTaP3-CB has a similar tolerability profile to other acellular vaccines and is associated with similar rates of local tenderness, irritability, fever (> or =40 degrees C) and persistent crying. Comparative trials have shown that infants immunised with DTaP3-CB had a lower incidence of pain at the site of injection and fever (> or =38 degrees C) compared with other acellular vaccines, although this may have little clinical significance. Concomitant administration of DTaP3-CB with hepatitis B, oral polio or Haemophilus influenzae type B vaccines did not affect the immunogenicity of these other paediatric vaccines.
CONCLUSION: Data from clinical trials with DTaP3-CB vaccine indicate that this vaccine induces high and long lasting efficacy. It is at least as efficacious as most whole cell vaccines and generally similar in efficacy to the most efficacious acellular pertussis vaccines containing 3 or more pertussis antigens. DTaP3-CB is better tolerated than whole cell vaccines and has a similar tolerability profile to other acellular vaccines; the possible lower risk of severe adverse events remains to be confirmed. The low reactogenicity of DTaP3-CB is likely to make it well tolerated and therefore well accepted for the immunisation of infants, thereby enabling wider implementation of vaccination programmes.