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 long-lasting. 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.