CDC surveillance data reveal a notable shift in the HIV/AIDS epidemic in the United States, with a higher proportion of new AIDS diagnoses today occurring among women, racial/ethnic minorities, low-income groups, and young MSM. Early in the HIV/AIDS epidemic, infections were mainly seen among White, urban, MSM or male IDUs. However, over the past 25 years, the boundaries between groups at greater and lesser risk for contracting the virus have been dissolving, with the diversity of those potentially at risk rapidly increasing. Heterosexual sex has now become a major transmission route for HIV and is a leading cause of infection among women, especially within minority communities. In fact, the proportion of total AIDS cases attributed to heterosexual transmission has increased sixfold since 1989 from 5 percent to 31 percent.

Emerging trends in HIV infection include an increase in new infections among MSM, after years of decline. This increase has been associated with a resurgence of risky sexual behavior linked to the use of methamphetamine and other club drugs. While the link between HIV infection and methamphetamine abuse is not established for heterosexuals, data shows an association between methamphetamine use and risky sexual behavior.

Proportion of AIDS Cases Among Adults and Adolescents,
by Transmission Category and Year of Diagnosis,
1985-2003—United States Note: Data adjusted for reporting delatys and for estimated proportional redistribution of cases in persons initially reported without an identified risk factor.
Source: CDC, U.S. Department of Health and Human Services.