Aventis submitted a Biologics Licensing Application (BLA) to the US FDA for marketing approval of Adacel (Tetanus Toxoid and Reduced Diphtheria Toxoid and Acellular Pertussis Vaccine Adsorbed) for prevention of tetanus, diphtheria and pertussis in adolescents and adults aged 11 through 64 years. The BLA for this candidate vaccine was submitted by Aventis Pasteur, the vaccines business of Aventis.

A vaccine is currently available to protect children against pertussis up to 7 years of age. The diphtheria, tetanus and pertussis (DTaP) vaccine is generally administered in five doses between the ages of 2 months and 6 years of age. However, the vaccine does not offer lifelong protection against pertussis, and it is believed that immunity wanes by adolescence. While a tetanus and diphtheria booster immunization is available starting at age 11, a pertussis booster is not.

The Adacel tetanus, diphtheria and pertussis vaccine will be referred to as a "Tdap" vaccine; the children's vaccine to prevent these same diseases is known as "DTaP." The pertussis components in Adacel vaccine are based on the acellular pertussis formulation in Daptacel, Diphtheria and Tetanus Toxoids and Acellular Pertussis Vaccine Adsorbed (DTaP vaccine), which was successfully introduced by Aventis Pasteur in the US in 2002.

The regulatory submission for Adacel vaccine is based on results of clinical studies involving more than 7,200 clinical trial participants. The vaccine has shown an excellent safety and immunogenicity profile. Adacel vaccine is currently approved and marketed in Canada and Germany, release from Aventis said.

"Pertussis continues to be an important public health issue, in part because adolescents and adults may not even be aware that they have the disease and that they can transmit it to vulnerable infants and younger children," said David R Johnson, director, scientific and medical affairs, Aventis Pasteur. "We've already had great success in the prevention of tetanus and diphtheria in the US and believe that the introduction of a combination vaccine that also protects against pertussis in adults and adolescents will help to counter ongoing transmission of this disease," he added.

Reported cases of pertussis, commonly known as whooping cough, clearly are on the rise in the US. In 2002, 9771 cases were reported to the US Centres for Disease Control and Prevention (CDC), the highest number of such reports in more than 30 years. Preliminary counts of pertussis reports for 2003 exceed 10,000, while reporting thus far in 2004 is at an even faster pace. However, it is estimated that only 12 per cent of pertussis cases are actually reported and that under-reporting may be greatest among adolescents and adults.