HIV/AIDS

Human immunodeficiency virus infection and acquired immunodeficiency syndrome (HIV/AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV),^[9][10][11] a retrovirus.^[12] Following initial infection an individual may not notice any symptoms, or may experience a brief period of influenza-like illness.^[4] Typically, this is followed by a prolonged incubation period with no symptoms.^[5] If the infection progresses, it interferes more with the immune system, increasing the risk of developing common infections such as tuberculosis, as well as other opportunistic infections, and tumors which are otherwise rare in people who have normal immune function.^[4] These late symptoms of infection are referred to as acquired immunodeficiency syndrome (AIDS).^[5] This stage is often also associated with unintended weight loss.^[5]

HIV is spread primarily by unprotected sex (including anal and vaginal sex), contaminated blood transfusions, hypodermic needles, and from mother to child during pregnancy, delivery, or breastfeeding.^[13] Some bodily fluids, such as saliva, sweat and tears, do not transmit the virus.^[14] Oral sex has little to no risk of transmitting the virus.^[15]

Methods of prevention include safe sex, needle exchange programs, treating those who are infected, as well as both pre- and post-exposure prophylaxis.^[4] Disease in a baby can often be prevented by giving both the mother and child antiretroviral medication.^[4]

Known as the Berlin Patient and the London Patient, two individuals have been reported cured of AIDS and the NIH and Gates Foundation pledged $200 million focused on developing a global cure for AIDS.^[16] While there is no broadly available cure or vaccine, antiretroviral treatment can slow the course of the disease and may lead to a near-normal life expectancy.^[5][6] Treatment is recommended as soon as the diagnosis is made.^[17] Without treatment, the average survival time after infection is 11 years.^[7]

In 2021, about 38 million people worldwide were living with HIV and 650,000 deaths had occurred in that year.^[8] An estimated 20.6 million of these live in eastern and southern Africa.^[18] Between the time that AIDS was identified (in the early 1980s) and 2021, the disease has caused an estimated 40 million deaths worldwide.^[19] HIV/AIDS is considered a pandemic—a disease outbreak which is present over a large area and is actively spreading.^[20]

HIV made the jump from other primates to humans in west-central Africa in the early-to-mid 20th century.^[21] AIDS was first recognized by the United States' Centers for Disease Control and Prevention (CDC) in 1981 and its cause—HIV infection—was identified in the early part of the decade.^[22]