Human immunodeficiency virus (HIV) is an infection that attacks the body’s immune system, specifically the white blood cells called CD4 cells. HIV destroys these CD4 cells, weakening a person’s immunity against infections such as tuberculosis and some cancers.

WHO recommends that every person who may be at risk of HIV should access testing. People diagnosed with HIV should be offered and linked to antiretroviral treatment as soon as possible following diagnosis. If taken consistently, this treatment also prevents HIV transmission to others.