Pertussis in adults: possible use of booster doses for control.

Adolescents and adults represent an increasing proportion of the relatively fixed number of reported pertussis cases in the United States each year. Widespread use of pertussis vaccine in the pediatric population has resulted in more individuals reaching adulthood without having had the disease. Since pertussis vaccine is not recommended for routine use in persons over 6 years of age, the loss of vaccine immunity with time after immunization provides a continuous supply of susceptibles (beginning during the teen years) in the population. It has been suggested that whole cell pertussis vaccine is more reactogenic in adults than in children. The data, however, indicate that the rates of local and systemic reactions are equivalent to those reported for children receiving routine pertussis immunization. Nevertheless, because pertussis is not a life-threatening illness in adults, the allegations against and perceptions about the vaccine cannot be overcome and whole cell PDT will never be used routinely in adults. The development of acellular pertussis vaccines, however, provides a novel opportunity for consideration of immunization of the adult population. In phase I trials, acellular pertussis vaccine has been given to adults with minimal reactions and good immunogenicity. Preparations containing pertussis toxin (PT) and filamentous hemagglutinin (FHA) were associated with greater frequency of local reactions to doses following the first. These data indicate that routine booster immunization of the adult population, probably every 10 years with tetanus-diphtheria toxoids (Td), is feasible and might be beneficial in control of pertussis. A major hurdle in consideration of such a policy will be theoretical acceptance by the medical community and lay public.