Although the number of newly reported AIDS cases continues to decrease in the United States as a result of highly active antiretroviral therapy, the overall number of AIDS cases remains significant. Data adjusted for delays in reporting showed adults and adolescents diagnosed with AIDS to be an estimated 49,689 in 1997 and 44,296 in 1998. The proportion of cases among women increased slightly in 1998, accounting for approximately one fourth of the cases.
AIDS incidence data increasingly reflect those for whom medical treatments were not available, effective or used. Some persons receive their AIDS diagnosis at the same time they learn about their HIV infection, precluding therapies to prevent an AIDS diagnosis. Others may have been infected for many years and have recently developed AIDS despite medical treatments and therapies. For these reasons, current AIDS incidence data should be interpreted with caution and can no longer be used to describe patterns in HIV incidence.
This report will provide more detailed information about the epidemiology of HIV/AIDS at the national level to complement the information contained in the semiannual HIV/AIDS surveillance reports. It presents AIDS cases cross-tabulated by sex, race/ethnicity, age group at diagnosis, and risk exposure category for 1997 and for 1998. This presentation shows the distribution of age at diagnosis within sex, race/ethnicity, and risk exposure categories. For example, differences in the age distribution for persons infected with HIV through injection drug use versus those infected through heterosexual contact are evident in some racial/ethnic groups. Although AIDS incidence is affected by HIV incidence trends, and testing and treatment patterns, state and local areas can present local data similar to this report to identify populations, such as heterosexually active minority youth, for prevention interventions.