Economic burden of pertussis and the impact of immunization.

Although routine use of vaccines has diminished the incidence of pertussis disease, it has not eliminated the pathogen. Epidemiologic data confirm that pertussis remains a significant health problem in all age groups. Disease burden is highest in infants, in whom pertussis disease frequently leads to severe complications and mortality, although it is also a significant health burden in adolescents and adults, in whom the reported incidence of pertussis is increasing. The Global Pertussis Initiative reviewed the literature to find data that express the economic impact of this health burden and to review economic evaluations of pertussis immunization. Although only limited data on the direct and indirect costs of pertussis are available, they suggest that it poses a significant economic burden and indicate that the direct medical costs of pertussis depend on the rate of hospitalization and the severity of complications, and are highest in infants. The indirect costs of pertussis also appear to be considerable, particularly among adults, in whom the disease reduces work productivity, because of either personal illness or child care responsibilities. Several health economic models on the cost effectiveness of childhood immunization strategies have been published, and although constrained by missing data, have generally found childhood immunization strategies to be cost-effective. Economic analyses of adolescent and adult immunization strategies have also been conducted, but the findings of these studies have been inconsistent. The most recent evaluations, using much higher estimates of incidence than reported previously, suggest that immunization of adolescents and specific adult subgroups may be cost-effective. The literature review confirmed that the economic burden of pertussis is substantial, but there are gaps in existing information. In the short term, further economic analyses are required, particularly of adolescent and adult immunization. More importantly, collection of primary epidemiologic and economic data should be undertaken in parallel. Despite the existing gaps in data, further research using the most current data should facilitate decisions on new vaccination strategies by describing conditions for favorable results and quantifying the margin of uncertainty.