HIV (human immunodeficiency virus) is a virus that attacks the bodys immune system, and if left untreated, it can lead to AIDS (acquired immunodeficiency syndrome) . HIV is a sexually transmitted infection (STI) that can also be spread by contact with infected blood and from illicit injection drug use or sharing needles. It can also be spread from mother to child during pregnancy, childbirth, or breastfeeding. HIV is caused by two lentiviruses, HIV-1 and HIV-2, which are the result of multiple cross-species transmissions of simian immunodeficiency viruses (SIVs) naturally infecting African primates. Most cases of HIV in the UK are caused by having sex with a person who has HIV without using a condom.

The virus attacks the helper T-cells of the immune system, leaving it weakened, and without medication, it may take years before HIV weakens the immune system to the point that AIDS develops. HIV initially makes a person feel sick with flu-like symptoms, and then it can hide in the body for a long time without causing noticeable symptoms. During that time, it slowly destroys T-cells. When T-cells get very low or a person begins to get certain illnesses that people with healthy immune systems don’t get, HIV has progressed to AIDS.

There is currently no effective cure for HIV/AIDS, but medications can control the infection and prevent progression of the disease. Antiviral treatments for HIV have reduced AIDS deaths around the world, and international organizations are working to increase the availability of prevention measures and treatment in resource-poor countries. Knowing your HIV status helps you make healthy decisions to prevent getting or transmitting HIV, and HIV treatment significantly reduces the risk of someone with HIV passing it on.