HIV

HIV (human immunodeficiency virus) is a retrovirus that attacks the body's immune system, specifically targeting CD4 cells (T cells), which help the immune system fight off infections. If left untreated, HIV reduces the number of CD4 cells in the body, making the person more likely to get infections or infection-related cancers. The virus is transmitted through contact with certain body fluids from a person who has HIV, most commonly during unprotected sex or through sharing injection drug equipment. HIV can also be transmitted from mother to child during pregnancy, birth or breastfeeding. Over time, HIV can destroy so many CD4 cells that the body cannot fight off infections and disease, leading to acquired immunodeficiency syndrome (AIDS), the most severe phase of HIV infection. Symptoms of HIV vary depending on the stage of infection, with early-stage symptoms including fever, headache and rash, whilst later stages may involve weight loss, chronic diarrhoea and opportunistic infections. Antiretroviral therapy (ART) can control the virus, allowing people with HIV to live long and healthy lives whilst also preventing transmission to others. Sub-Saharan Africa bears the highest burden of HIV globally, with millions of people living with the virus and significant public-health and economic impacts. Prevention strategies include condom use, pre-exposure prophylaxis (PrEP), voluntary medical male circumcision and harm reduction programmes for people who inject drugs. The virus was first identified in the early 1980s and has since become one of the world's most significant public-health challenges, prompting extensive research, treatment programmes and advocacy efforts.