Neurocognitive decline in HIV infection

More than 34 million people worldwide are currently estimated to live with HIV infection. (Note: Although there are two types of HIV, only one is endemic in the United States - HIV type 1 [HIV-1], which is denoted throughout simply as "HIV.") Nearly 7,000 people worldwide are newly infected with HIV on a daily basis, which is about 300 people per hour.¹ In the United States, there have been dramatic declines in the annual number of new HIV infections, from a peak of about 130,000 in the mid-1980s to a low of approximately 50,000 in the early 1990s. The rate of new infections increased in the late 1990s, followed by a leveling-off pattern since 2000 to about 55,000 new cases per year. The United States incidence figure had been previously estimated at 40,000 per year until a revision for those who were unknown to be seropositive was included.² This figure has remained stable for more than a decade despite the ongoing attempts of the Centers for Disease Control and Prevention (CDC) to reduce it.