Pertussis vaccines and the challenge of inducing durable immunity

Pertussis has re-emerged as an important public health concern. In the 1990s whole-cell pertussis vaccines were replaced with less reactogenic acellular vaccines consisting of purified pertussis components. However, recent data show that protection from acellular pertussis vaccines is not longlasting. Antibody levels wane rapidly following vaccination, likely a result of the inability of acellular pertussis antigens to stimulate long-lasting B cell memory. In addition, T cell responses to acellular pertussis vaccines are mixed Th2/Th1, while whole-cell pertussis vaccination and infection stimulate Th17 responses, important for host defense against extracellular mucosal pathogens. Consistent with this T cell skewing, acellular vaccines did not prevent colonization or transmission following challenge in nonhuman primates while whole-cell vaccinated and previously infected animals cleared the infection more rapidly.