Epidemiology of HIV infection in the United States: implications for linkage to care.

The epidemiology of human immunodeficiency virus (HIV) infection in the United States has changed significantly over the past 30 years. HIV/acquired immune deficiency syndrome (HIV/AIDS) is currently a disease of greater demographic diversity, affecting all ages, sexes, and races, and involving multiple transmission risk behaviors. At least 50,000 new HIV infections will continue to be added each year; however, one-fifth of persons with new infections may not know they are infected, and a substantial proportion of those who know they are infected are not engaged in HIV care. Barriers to early engagement in care may be specific to a demographic group. In this paper, the current epidemiology of HIV/AIDS in the United States is reviewed in order to understand the challenges, successes, and best practices for removing the barriers to effective diagnosis and receipt of HIV care within specific demographic groups.