Any discussion of the prospects for an improved vaccine against Bordetella pertussis must include a review of the history of the existing pertussis vaccine. The efficacy of this vaccine is well documented, but its association with a significant rate of adverse effects has made it a focus of controversy. Widespread discussion of the risks of the current pertussis vaccine may be eroding confidence in childhood immunization programs in general (see Chapter 8). A forthcoming report from the Institute of Medicine’s Committee on Public-Private Sector Relations in Vaccine Innovation will address the frequency of untoward reactions to vaccines and problems arising from their occurrence. Hence, these issues will be mentioned only briefly in this appendix. The disease burden and benefits sections of this appendix are somewhat different from those of the other appendixes, because the analysis of pertussis vaccine benefits focuses on incremental rather than total benefits.

Pertussis (whooping cough) is a bacterial infection caused by Bordetella pertussis, and characterized by severe paroxysmal coughing that persists for weeks (Mortimer, 1982). The disease primarily affects infants and young children, and its morbidity and mortality rates generally are inversely related to age. Infants do not acquire adequate maternal immunity, so they are highly susceptible to infection.

The infection is localized in the respiratory tract, especially on the epithelial surfaces of the bronchial tree. The cause of the paroxysms of coughing (the whoop) is uncertain: it may be a result of the tenacious nature of the secretions, or a direct effect of the organism or its toxins on the central nervous system. Immediate complications include encephalopathy and convulsions, pulmonary atelectasis, and