Can increasing awareness of HIV seropositivity reduce infections by 50% in the United States?

Background: In 2003, US Centers for Disease Control and Prevention (CDC) announced an HIV prevention initiative that emphasized increasing the proportion of persons living with HIV who are aware of their positive serostatus. Previously, CDC set a national HIV prevention goal of reducing new infections by 50% by 2005, with increasing serostatus awareness a central goal. The objectives of this article are to examine the national epidemiologic consequences of increasing serostatus awareness and the important question of how far increasing awareness could lead toward achieving CDC's goal of a 50% reduction in incident infections. Methods: Scenario analysis methods were used to project incident HIV infections over 1- and 10-year time horizons at varying levels of HIV seropositivity awareness. Because HIV transmission rates are several times higher for those who are unaware of their HIV seropositivity than for those who are aware, we modeled the effects of increasing awareness via HIV counseling and testing and moving people from the higher to the lower transmission category. Results: Increasing awareness of HIV seropositivity via HIV counseling and testing in the United States from a baseline 75% to 95% has the potential of reducing new infections by as much as 32% in a single year. Achieving the national goal of 50% reduction seems out of reach, however. Conclusions: Reduction of new infections by 50% in the United States requires a combination of prevention services to reduce further the already low HIV transmission rate from persons aware of their HIV seropositivity and HIV risk reduction interventions for at-risk persons. Counseling and testing alone seems insufficient to meet the 50% incidence reduction goal.