HIV, or human immunodeficiency virus, attacks cells that help the body fight infection. AIDS is the most advanced stage of HIV infection when the immune system has been severely damaged. Effective treatment means most people receiving modern HIV care do not develop AIDS.

How HIV is transmitted

HIV can be transmitted through certain body fluids, most commonly during sex without effective prevention or by sharing injection equipment. It can also pass during pregnancy, birth or breastfeeding without appropriate care. It is not spread by ordinary contact such as shaking hands, sharing dishes, using the same toilet, or mosquito bites.

Testing is the only way to know

Symptoms cannot confirm or exclude HIV. Some people have a flu-like illness soon after infection, while others have no noticeable symptoms for years. A suitable HIV test is the only way to know a person’s status, and timing matters because tests have window periods.

Treatment and prevention

HIV.gov explains that antiretroviral therapy can reduce the amount of virus in the blood to an undetectable level. People who take treatment as prescribed and maintain an undetectable viral load do not transmit HIV to sexual partners.

Pre-exposure prophylaxis can reduce risk before exposure for eligible people. Post-exposure prophylaxis is time-sensitive medicine started after a possible exposure; urgent professional advice is needed because it must be started promptly.

HIV can affect anyone. Stigma and stereotypes interfere with testing and care. Anyone concerned about an exposure should contact a qualified healthcare service for confidential testing and current advice.