The expanded knowledge of the components of Bordetella pertussis has led to the production of new vaccines consisting of one or more components of the organism. The vaccines have been found to be safe and immunogenic in infants and children. Early efficacy studies failed to determine what component of the vaccine and what level of antibody were needed for protection; additional studies with many more vaccines are currently in progress. The role of adults as reservoirs of B. pertussis infections and as victims of symptomatic disease has also been appreciated. Component vaccines have been found to be safe and immunogenic in adults. There is reason to hope that within the next several years the information derived from ongoing and planned studies will support the general use of component acellular pertussis vaccines for the routine immunization of adults and children alike.