Immunogenicity of an acellular pertussis vaccine composed of genetically inactivated pertussis toxin combined with filamentous hemagglutinin and pertactin in infants and children

We studied the immunogenicity of an acellular pertussis vaccine composed of genetically detoxified pertussis toxin (PT-9K/129G), filamentous haemagglutinin, and a 69-kilodalton protein, pertactin, in 30 children aged 12 to 24 months and in 80 infants aged 2 to 4 months. A significant increase of the neutralizing titer and of the titers against pertussis toxin, filamentous hemagglutinin, and pertactin, as determined by enzyme-linked immunosorbent assay, was achieved after three doses of vaccine in all the children; a significant increase of these antibody titers was obtained in 100%, 96.1%, 93.5%, and 98.7% of the infants, respectively.