acellular vaccines against pertussis and methods for their preparation

Acellular pertussis vaccines comprise purified toxin or toxoid thereof, filamentous haemagglutinin, pertactin and fimbrial agglutinogens formulated to confer protection to at least 70% of members of an at-risk population. The fimbrial agglutinogens may be prepared from a Bordetella strain, particularly a B.pertussis strain, by a multiple step procedure involving extraction of the fimbrial agglutinogens from cell paste and concentrating and purifying the extracted material.