General Information

Daptacel is a diptheria and tetanus toxoids and acellular pertussis vaccine adsorbed (DTaP), approved for routine immunization in infants and children six weeks through six years of age. It is administered via intramuscular injection in four consecutive doses of the five dose immunization series. The four doses are given at approximately two months, four months, six months and six months after the third dose.

Mechanism of Action

Daptacel is a DTaP vaccine given in four consecutive intramuscular doses. The DTaP is about 10 times less likely to cause adverse reactions than the older DTP is. While the DTP contains the whole, inactivated pertussis bacteria, the DTaP uses only the parts of the bacteria that help the infant or child develop immunity to it and leaves behind the other parts that may have been responsible for many of the DTP's adverse effects.

Side Effects

Adverse events associated with the use of Daptacel may include (but are not limited to) the following:

• Drowsiness
• Irritability
• Anorexia
• Injection site irritation

Clinical Trial Results

Approval of Daptacel is supported by data from clinical trials conducted in Sweden, Canada and the United States. In Sweden, close to 1,000 infants were randomized to receive one of four vaccines for the treatment of pertussis. These included Daptacel, another investigational acellular pertussis vaccine, whole-cell pertussis DTP vaccine or DT vaccine as placebo. During a follow-up two years after administration of the third dose, the protective efficacy of Daptacel was 85%. Identical studies performed in the United States and Canada produced similar results.

Canadian and United States clinical studies evaluated Daptacel as a preventative for diptheria and tetanus in children. After four doses of the vaccine, the portion of children with diptheria and tetanus antitoxin levels greater then or equal to a serological correlate of protection defined by the Panel on Review of Bacterial Vaccines and Toxoids, was close to 100% in both studies.