There are many myths and misconceptions about how long HIV lives and is infectious in the air or on a surface outside the body.
Unless the virus is kept under specific conditions, the true answer is not very long.
Although it causes a serious disease that can’t be cleared by the body, HIV is very fragile in the outside environment. It quickly gets damaged and becomes inactive, or “dies.” Once inactive, HIV can’t become active again, so it’s the same as if it’s dead.
How does HIV spread?
HIV spreads when blood or certain bodily fluids that have high amounts of active virus (like semen, vaginal fluids, rectal fluids, or breast milk) are exposed to one’s bloodstream.
For a person to contract HIV, there must be enough active virus in the fluid that encounters the bloodstream. This can occur through:
- a mucous membrane, or “moist skin,” such as in the mouth, rectum, penis, or vagina
- a significant opening in the skin
Transmission of the virus most often happens during anal or vaginal sex, but it can also occur by sharing needles.
Factors that affect the survival of HIV outside the body include:
- Temperature. HIV stays alive and active when kept in the cold but is killed by heat.
- Sunlight. Ultraviolet light in sunshine damages the virus, so it’s no longer able to reproduce.
- Amount of virus in the fluid. Generally, the higher the level of HIV virus in the fluid, the longer it will take for all of it to become inactive.
- Level of acidity. HIV survives best at a pH around 7 and becomes inactive when the environment is even just a little more or less acidic.
- Environmental humidity. Drying will lower the viral concentration of active virus as well.
When any of these factors aren’t perfect for HIV in its environment, survival time of the virus goes down.
How long does HIV live outside the body in the environment?
HIV can’t survive for long in the environment. When fluid leaves the body and is exposed to air, it begins to dry up. As drying occurs, the virus becomes damaged and can become inactive. Once inactive, HIV is “dead” and no longer infectious.
Some research show that, even at levels much higher than usually found in the bodily fluids and blood of people with HIV, 90 to 99 percent of the virus is inactive within hoursTrusted Source of being exposed to air.
However, even though exposure to the environment can inactivate the virus, studiesTrusted Source have found that active virus can be detected outside of the body for at least several daysTrusted Source, even as the fluid dries.
So, can you get HIV from a surface, such as a toilet seat? In short, no. The amount of active virus that would be able to transmit an infection in this scenario is negligible. A case of transmission from a surface (such as a toilet seat) has never been reported.