Pertussis in adults: epidemiology, signs, symptoms, and implications for vaccination.

Transmission of pertussis among adults is being increasingly recognized. About 1 or 2 in 1,000 adolescents and adults develop pertussis each year, > or = 12% of persons with acute cough illnesses of at least 1-2 weeks' duration have evidence of pertussis infection, and adults have been the source of pertussis for younger children. The advent of acellular pertussis vaccines, if safe and effective in adults, offers the opportunity to prevent transmission of pertussis in older populations. Several issues should be clarified before routine immunization is recommended, including the health burden of pertussis in adults and adolescents to be prevented by vaccination and how much morbidity resulting from pertussis in infants and children would be indirectly prevented. Preliminary studies suggest that pertussis vaccines are safe and immunogenic in adults. Potential recommendations for future vaccination might include all adolescents and adults at 10-year intervals along with the adult tetanus-diphtheria toxoids booster. Cost-benefit or cost-effectiveness analyses would be useful in developing vaccination policies for adults.