Worldwide, approximately 36 million people are infected with HIV. The number of new infections has been declining in most geographic areas including sub-Saharan Africa due to a larger number of persons receiving antiretroviral therapy (ART) and the uptake of new prevention methods. Prevalence in many areas has either stabilized or gradually increased due to prolonged survival. The US epidemic has remained stable, with approximately 1.2 million persons living with HIV. There are fewer AIDS deaths and approximately 40,000–50,000 new infections yearly, leading to an overall increase in HIV prevalence in the United States. Globally, most new infections are via heterosexual transmission, with more than half of new infections occurring in women. In Europe and the United States, the largest number of new infections is occurring in men who have sex with men. Due to the progressive uptake of ART, mother-to-child transmission has declined significantly throughout the world.