Bordetella pertussis is a human-specific pathogen that causes whooping cough. The use of pertussis whole-cell vaccines in infants and toddlers led to decreased circulation of the bacterium in the child population and a marked decrease in the incidence of the disease. However, vaccine does not result in life-long immunity; indeed, the circulation of the bacterium has not been controlled in the adult population. Universal adult booster immunization is now possible using pertussis acellular vaccines, which target-and are thus likely to control-the virulence of this bacterium.