F2 and pertussis: Several aP vaccines are available differing by the number of Bp antigens that they contain, their dose, as well as their formulation; currently licenced variations contain alum adjuvant and between one to five purified, stabilised, and chemically or genetically modified (detoxified) pertussis antigens, including pertussis toxin (PT, at least), filamentous haemagglutinin (FHA), pertactin (PRN), and fimbrial proteins 2 (FIM2) and 3 (FIM3).