^a Total cost assumes a direct to indirect cost ratio of 3:1 (total cost = direct cost × 1.33); this is based on computed ratios for chlamydia of 1:1 (Washington AE, et al., 1987; see above); pelvic inflammatory disease of 2:1 (Washington AE, Katz P. Cost of and payment source for pelvic inflammatory disease. Trends and projections, 1983 through 2000 [see comments]. JAMA 1991;266:2565-9), and hepatitis B of 1:1 (Hepatitis Branch, CDC, unpublished data, 1996).

^b Bacterial STD, herpes simplex virus infection, and cervical cancer direct costs estimates from Joanna E. Siegel, Sc.D., Harvard School of Public Health (Appendix D of the present report). Estimate assumes 70 percent of cervical cancer is STD-related.

^c Human papillomavirus direct cost estimate provided by Laura Koutsky, Ph.D., Center for AIDS and STD, University of Washington, Seattle, based on data from Medicaid and other sources. Cost estimate excludes cost of HPV-related cervical cancer.

^d Hepatitis B virus infection direct costs based on unpublished data from the Hepatitis Branch, Centers for Disease Control and Prevention, Atlanta. Assumes half of estimated cases are sexually transmitted.

^e Estimate assumes that the non-pelvic-inflammatory-disease-related costs for chlamydia are approximately $462 million, or approximately 30.5 percent of total chlamydial costs (Washington AE, Johnson RE, Sanders LL. Chlamydia trachomatis infections in the United States: what are they costing us? JAMA 1987;257:2070-2), and the non-pelvic-inflammatory-disease-related costs for gonorrhea are $96.4 million or the cost of just primary treatment for gonorrhea (Appendix D of present report).

^f HIV/AIDS estimates provided by James G. Kahn, M.D., M.P.H., Institute for Health Policy Studies, University of California, San Francisco, based on data in Hellinger FJ. The lifetime cost of treating a person with HIV. JAMA 1993;270:474-8; CDC. HIV/AIDS surveillance report. Atlanta: Centers for Disease Control and Prevention, 1995;7(2); and Rosenberg PS. Scope of the AIDS epidemic in the United States. Science 1995;270:1372-5. Does not reflect costs of more recently recommended therapeutic regimes for this infection.