Lyme disease produces a diverse clinical picture that can include seri
ous and potentially debilitating cardiac, neurologic, joint, and skin
involvement. It is characterized in three stages-early localized (stag
e I), early disseminated (stage II), and late disseminated (stage III)
-and medical management is highly dependent on the stage at which the
patient presents and the physician's awareness of available treatment
options. This study was conducted to establish the medical and economi
c burden of Lyme disease in the overall US population, which included
determining its endemicity in high-risk states and counties, describin
g current treatment patterns, measuring direct and indirect costs, and
defining the cost burden by age group (<18 years and greater than or
equal to 18 years of age). Medical, epidemiologic, and economic data w
ere collected, and an algorithm was developed representing the natural
course of Lyme disease and the progress of health states over time fo
llowing medical intervention. Using an annual mean incidence of 4.73 c
ases of Lyme disease per 100,000 population in the decision analysis m
odel yielded an expected national expenditure of $2.5 billion (1996 do
llars) over 5 years for therapeutic interventions to prevent 55,626 ca
ses of Lyme disease sequelae. This estimate included both direct medic
al and indirect costs. However, there is evidence of considerable vari
ation in incidence within states. Our findings support development of
vaccination strategies for specific target groups.