Global epidemiology of HIV.

The number of persons living with HIV worldwide reached approximately 35.3 million in 2012. Meanwhile, AIDS-related deaths and new HIV infections have declined. Much of the increase in HIV prevalence is from rapidly increasing numbers of people on antiretroviral treatment who are now living longer. There is regional variation in epidemiologic patterns, major modes of HIV transmission, and HIV program response. It is important to focus on HIV incidence, rather than prevalence, to provide information about HIV transmission patterns and populations at risk. Expanding HIV treatment will function as a preventive measure through decreasing horizontal and vertical transmission of HIV. Published by Elsevier Inc.