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Transmission

HIV/AIDS Awareness

How Do You Get HIV?

Certain body fluids from an HIV-infected person can transmit HIV.

These body fluids are:

  • Blood
  • 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.

For more information, see CDC’s HIV Basics: HIV Transmission.

How id HIV spread?

Approximately 50,000 new HIV infections occur in the United States each year. In the U.S., HIV is spread mainly by:

  • Having sex with someone who has HIV. In general:
    • Anal sex (penis in the anus of a man or woman) is the highest-risk sexual behavior. Receptive anal sex (“bottoming”) is riskier than insertive anal sex (“topping”).
    • Vaginal sex (penis in the vagina) 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.

Having an undetectable viral load greatly lowers the chance that a person living with HIV can transmit the virus to a partner, but there is still some risk. “Viral load” refers to the amount of HIV in an infected person’s blood. An “undetectable viral load” is when the amount of HIV in a person’s blood is so low that it can’t be measured. antiretroviral therapy (ART) reduces a person’s viral load, ideally to an undetectable level, when taken consistently and correctly. However, a person with HIV can still potentially transmit HIV to a partner even if they have an undetectable viral load, because:

  • HIV may still be found in a person’s genital fluids (e.g., semen, vaginal fluids). The viral load test only measures virus in a person’s blood.
  • A person’s viral load may go up between tests. When this happens, they may be more likely to transmit HIV to partners.
  • Sexually transmitted diseases (STDs) increase viral load in a person’s genital fluids.

For more information on how HIV is spread, see CDC’s HIV Basics: HIV Transmission.

Also, for more information about the risks from different types of HIV exposure, see CDC’s HIV Transmission Risk.

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Content source: CDC Division of HIV/AIDS Prevention | AIDS.gov
Image source: AIDS.gov