HIV, or the human immunodeficiency virus, attacks the cells that help you fight infection. It passes from person to person through bodily fluids like blood, semen, and breast milk. Here’s what happens when it gets outside the body.
Which Bodily Fluids Spread HIV?
The only bodily fluids that can carry the virus are:
- Semen (including pre-ejaculate)
- Vaginal fluid
- Rectal fluid
- Breast milk
To spread HIV, the fluids either have to go straight into your bloodstream (like from a needle) or touch mucous membranes -- areas like the inside of your mouth, vagina, or rectum. You can’t get HIV by sitting on a toilet seat or sharing dishes with an infected person.
How Long Does HIV Survive Outside the Body?
In general, the virus doesn’t live long once it’s outside of a human body. Studies show that HIV grown in the lab, when placed on a surface, loses most of its ability to infect -- 90% to 99% -- within several hours. And the level of virus tested was much higher than what’s found in bodily fluids. So contact with dried blood, semen, or other fluids poses little risk.
Tiny amounts of HIV have been found in saliva, poop, sweat, and tears. But research shows it poses little risk.
The virus can’t survive in water, so you don’t have to worry about swimming pools or hot tubs.
One study found HIV can live in used needles for over a month if the temperature and conditions are just right. That means sharing needles or syringes, like during drug use, raises your risk of infection.
How to Avoid Getting HIV
Abstinence, or not having sex, is the only type of protection that works every time. But if you are having sex, you can lower your risk if you:
- Use a condom every time you have sex
- Get tested for HIV and STDs
- Limit the number of people you have sex with
- Don’t inject yourself with drugs
Talk to your doctor right away if you think you’ve been exposed to the virus. They can help you figure out next steps.
HIV.gov: “What are HIV and AIDS?”
Avert: “Myths About HIV and AIDS.”
Stanford Health Care: “HIV and AIDS FAQs.”
CDC: “HIV Transmission,” “Prevention.”
University of California, Santa Barbara: “HIV and AIDS.”
University of Rochester Medical Center: “Infectious Diseases FAQs.”
Substance Use & Misuse: “Survival of HIV-1 in Syringes: Effects of Temperature During Storage.”
U.S. National Library of Medicine: “HIV Prevention.”