How Do You Get or Transmit HIV?
You can only get HIV by coming into direct contact with certain body fluids from a person with HIV who has a detectable viral load. These fluids are:
- Semen (cum) and pre-seminal fluid
- Rectal fluids
- Vaginal fluids
- Breast milk
For transmission to occur, the HIV in these fluids must get into the bloodstream of an HIV-negative person through a mucous membrane (found in the rectum, vagina, mouth, or tip of the penis); open cuts or sores; or by direct injection.
People with HIV who take HIV medicine daily as prescribed and get and keep an undetectable viral load have effectively no risk of sexually transmitting HIV to their HIV-negative partners.
How Is HIV Spread from Person to Person?
HIV can only be spread through specific activities. In the United States, the most common ways are:
- Having vaginal or anal sex with someone who has HIV without using a condom or taking medicines to prevent or treat HIV. Anal sex is riskier than vaginal sex.
- Sharing injection drug equipment (“works”), such as needles, with someone who has HIV.
Less common ways are:
- From mother to child during pregnancy, birth, or breastfeeding. However, the use of HIV medicines and other strategies have helped lower the risk of mother-to-child transmission of HIV to 1% or less in the United States.
- Getting stuck with an HIV-contaminated needle or other sharp object. This is a risk mainly for health care workers. The risk is very low.
HIV is spread only in extremely rare cases by:
- Having oral sex. But in general, the chance that an HIV-negative person will get HIV from oral sex with an HIV-positive partner is extremely low.
- Receiving blood transfusions, blood products, or organ/tissue transplants that are contaminated with HIV. The risk is extremely small these days because of rigorous testing of the U.S. blood supply and donated organs and tissues.
- 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.
- Contact between broken skin, wounds, or mucous membranes and HIV-infected blood or blood-contaminated body fluids.
- Deep, open-mouth kissing if both partners have sores or bleeding gums and blood from the HIV-positive partner gets into the bloodstream of the HIV-negative partner. HIV is not spread through saliva.
- Eating food that has been pre-chewed by a person with HIV. The contamination occurs when infected blood from a caregiver’s mouth mixes with food while chewing. The only known cases are among infants.
Does HIV Viral Load Affect Getting or Transmitting HIV?
Yes. Viral load is the amount of HIV in the blood of someone who has HIV. Taking HIV medicine (called antiretroviral therapy or ART) daily as prescribed can make the viral load very low—so low that a test can’t detect it (this is called an undetectable viral load).
People with HIV who take HIV medicine daily as prescribed and get and keep an undetectable viral load have effectively no risk of transmitting HIV to an HIV-negative partner through sex.
HIV medicine is a powerful tool for preventing sexual transmission of HIV. But it works only as long as the HIV-positive partner gets and keeps an undetectable viral load. Not everyone taking HIV medicine has an undetectable viral load. To stay undetectable, people with HIV must take HIV medicine every day as prescribed and visit their healthcare provider regularly to get a viral load test.
Ways HIV Cannot Be Spread
HIV is not spread by:
- Air or water
- Mosquitoes, ticks or other insects
- Saliva, tears, or sweat that is not mixed with the blood of a person with HIV
- Shaking hands; hugging; sharing toilets; sharing dishes, silverware, or drinking glasses; or engaging in closed-mouth or “social” kissing with a person with HIV
- Drinking fountains
- Other sexual activities that don’t involve the exchange of body fluids (for example, touching).
HIV can’t be passed through healthy, unbroken skin.
How Do You Get AIDS?
You can’t “catch” AIDS.
AIDS is the most advanced stage of HIV infection. If you have HIV and you are not on HIV treatment, eventually your body’s immune system will weaken and you will progress to AIDS.
People with AIDS have such badly damaged immune systems that they get a number of severe illnesses, called opportunistic infections.