HIV is spread from an infected person to another person through direct contact with some of the body’s fluids. It is not spread easily. Only certain body fluids from an HIV-infected person can transmit HIV:
- Semen (cum)
- Pre-seminal fluid (pre-cum)
- Rectal fluids
- Vaginal fluids
- Breast milk
These body fluids must come into contact with a mucous membrane or damaged tissue or be directly injected into your bloodstream (by a needle or syringe) for transmission to possibly occur. Mucous membranes are the soft, moist areas just inside the openings to your body. They can be found inside the rectum, the vagina or the opening of the penis, and the mouth.
In the United States, HIV is spread mainly by:
- Sexual intercourse with someone who has HIV. In general:
- Anal sex is the highest-risk sexual behavior. Receptive anal sex (“bottoming”) is riskier than insertive anal sex (“topping”).
- Vaginal sex is the second highest-risk sexual behavior.
- Having multiple sex partners or having sexually transmitted infections can increase the risk of HIV infection through sex.
- Sharing needles, syringes, rinse water, or other equipment (“works”) used to prepare injection drugs with someone who has HIV.
Less commonly, HIV may be spread by:
- Being born to an infected mother. HIV can be passed from mother to child during pregnancy, birth, or breastfeeding.
- Being stuck with an HIV-contaminated needle or other sharp object. This is a risk mainly for health care workers.
- Receiving blood transfusions, blood products, or organ/tissue transplants that are contaminated with HIV. This risk is extremely small because of rigorous testing of the US blood supply and donated organs and tissues.
- Eating food that has been pre-chewed by an HIV-infected person. The contamination occurs when infected blood from a caregiver’s mouth mixes with food while chewing, and is very rare.
- Being bitten by a person with HIV. Each of the very small number of documented cases has involved severe trauma with extensive tissue damage and the presence of blood. There is no risk of transmission if the skin is not broken.
- Oral sex—using the mouth to stimulate the penis, vagina, or anus (fellatio, cunnilingus, and rimming). Giving fellatio (mouth to penis oral sex) and having the person ejaculate (cum) in your mouth is riskier than other types of oral sex.
- Contact between broken skin, wounds, or mucous membranes and HIV-infected blood or blood-contaminated body fluids. These reports have also been extremely rare.
- Deep, open-mouth kissing if the person with HIV has sores or bleeding gums and blood is exchanged. HIV is not spread through saliva. Transmission through kissing alone is extremely rare.
HIV is NOT spread by:
- Air or water
- Insects, including mosquitoes or ticks
- Saliva, tears, or sweat
- Casual contact, like shaking hands, hugging or sharing dishes/drinking glasses
- Drinking fountains
- Toilet seats
HIV is not spread through the air and it does not live long outside the human body. People with HIV who are using antiretroviral therapy (ART) consistently and who have achieved viral suppression (having the virus reduced to an undetectable level in the body) are very unlikely to transmit the virus to their uninfected partners. However, there is still some risk of transmission, so even with an undetectable viral load, people with HIV should continue to take steps to reduce HIV transmission.
HIV may cause acquired immunodeficiency syndrome or AIDS.