In addition to diphtheria and tetanus toxoids, the entire childhood vaccination series of diphtheria–tetanus–acellular-pertussis (DTaP) vaccine contains inactivated pertussis toxin (Ptx) and one or more additional virulence-related bacterial components: filamentous hemagglutinin (Fha), pertactin (Prn), or fimbria (Fim) types 2 and 3. Here, CIAO3 is linked to pertussis.