Pertussis vaccines: The first hundred years.
Vaccines against pertussis have been used for more than a hundred years. This review describes the development of whole-cell (wP) and acellular pertussis (aP) vaccines, which, as DTP combination vaccines, have significantly reduced morbidity and mortality from pertussis, and which currently serve as the building blocks for a variety of vaccines used to immunize all infants worldwide. Two series of efficacy trials done in the 1950s for wP vaccines and in the 1990s for aP-vaccines have established standards for studying vaccine effectiveness. However, irrespective of their longtime use, critical aspects of pertussis vaccines remain unknown, including the exact mechanisms of protective immunity and a correlate of protection. Research to improve on the effectiveness and the duration of protection is ongoing, but although the vaccines are not perfect, only their continued use with a high coverage will ensure that infants and children are being protected from pertussis.