Background:  This presentation examines the current state of the US HIV/AIDS epidemic, strategies to reduce HIV transmission, and future directions that should be taken. In the United States, the epidemic is measured through a number of surveillance systems, which monitor cases of AIDS and HIV infection, high-risk behaviors, and HIV incidence. Based on data reported through 2005, the cumulative number of AIDS cases since the beginning of the epidemic is approaching 1 million, with deaths exceeding one-half million. More than 400,000 persons are living with AIDS. Cases increased in 2005, largely driven by increases among men having sex with men (MSM), the group accounting for the largest number of persons with AIDS. Case rates in black populations are 10 times higher than in white populations. Behavioral surveillance indicates continuing high-risk sexual activity in MSM. Newly implemented HIV incidence surveillance, based on serologic testing to detect recent infection, will be critical in tracking trends in the epidemic.

Results:  The most effective HIV interventions are biomedical (eg, blood donor screening, ART to prevent mother-to-child transmission), but behavioral interventions also play an important role. These interventions can be linked; eg, reduced high-risk activity is seen following the diagnosis of HIV. The effectiveness of other interventions (eg, microbicides, vaccines, pre-exposure prophylaxis) remains to be determined, while abstinence-only education appears to have little or no efficacy.

Conclusions:  Funding priorities for HIV prevention must include implementing what works and evaluating what might work. Prevention leadership in MSM and African American communities is needed to confront the enormous disparities of the epidemic. To be realistic about what can be done, the limits of public health in changing human behaviour must also be acknowledged.