Human immunodeficiency virus (HIV) is a sexually transmitted infection, which occurs by contact or transfer of blood, semen, pre-ejaculate, rectal fluids, vaginal fluids, and breastmilk.
HIV from the infected fluids must get into the bloodstream through a mucous membrane, open cuts or sores, or by direct injection.
HIV is usually spread during:
- Vaginal or anal sex without using a condom
- Through sharing injection drug equipment (e.g. needles)
The less common ways of HIV transmission are:
- From an infected mother to her infant during pregnancy, childbirth, or through breast milk
- Getting stuck with an HIV-contaminated needle (mainly a risk for healthcare workers)
- Through oral sex (extremely low risk)
- Receiving blood or organ/tissue from an infected person (extremely low risk in the U.S. due to rigorous testing)
- Being bitten by an infected person (only a risk if the skin is broken)
- Contact between broken skin or wounds
Although there is no cure for HIV, effective antiretroviral therapy (ART) ensures that infected individuals can live relatively normal lives and prevents the transmission of HIV. When ART is taken every day, it reduces the replication of HIV in the blood to an undetectable level. At the end of 2019, an estimated 59% of individuals on ART had achieved suppression of the HIV virus with no risk of transmitting the virus to others.