Epidemiological, clinical, and laboratory aspects of pertussis in adults.

In populations without immunization, pertussis is a high-incidence, endemic disease with cyclic epidemic peaks occurring every 2-5 years. The universal use of pertussis vaccines in children results in a marked reduction in incidence, but the frequency of disease cycles does not lengthen. This indicates that the organism (Bordetella pertussis) remains prevalent in the population. Studies of prolonged cough illnesses in adolescents and adults indicate that between 12% and 32% are the result of B. pertussis infection. Serological survey data indicate that all adults have been previously infected, and IgA antibody studies suggest that infections in adults are as frequent in the United States, where pertussis has been controlled, as in Germany, where pertussis has been epidemic. Because of the apparent reservoir of B. pertussis infections in adolescents and adults, I believe that B. pertussis circulation cannot be controlled by our present childhood immunization program. Acellular pertussis vaccines make adolescent and adult booster immunization programs possible, and these could lead to a decrease in the circulation of the organism.