In the early days of HIV, there was a widespread fear that the virus could be caught from any surface or interaction. Similar to all novel viruses – think COVID-19 – scientists were unsure of the exact transmission method HIV relied on at first, only later realizing it was primarily passed via bodily secretions.

But what happens if you come into contact with these bodily secretions? Can you still get infected? Or, to put the question more broadly, how long can HIV live outside the body?

It’s an important question, not just for patients but for everyone from healthcare workers to cleaners. After all, if you can contract HIV from touching bodily secretion, is a toilet seat even safe?

We’re clearing up the confusion about how long HIV can last outside the body below – and we’ll explain when you should be worried.

HIV is spread when blood or particular bodily fluids gain access to your bloodstream – especially if there is a high amount of active virus.

Potential “at-risk” bodily fluids include blood, semen, vaginal fluids, rectal fluids, and breast milk. There is no risk from saliva, skin secretions, or other bodily fluids.

To infect another person, the bodily fluids must enter the body via:

• Injection, e.g., sharing needles or blood transfusion
• A break in the skin, e.g., a cut or wound
• A mucous membrane, e.g., mouth, rectum, penis, or vagina.

The most common method of transition is anal or vaginal sex, though sharing needles also carries significant risk.

Viruses aren’t typically “alive” in the traditional sense of the word – though the line is a little blurry. To be alive, an organism must be able to reproduce on its own or with a member of the same species. Viruses, on the other hand, rely on our cells to churn out new copies.

The better question is, when do viruses stop being infectious outside the body?

The answer: within a few hours. Within hours of exposure to air, 90% to 99% of HIV particles are inactive. Active viruses can still be detected outside the body for several days, even after the fluid has dried.

There’s no need to be concerned. Even with a small amount of active virus, the amount is so negligible as to carry no risk of infection. In fact, there’s never been a reported case of HIV from a toilet seat.

If HIV is never “alive” to begin with, why does it stop being active after leaving our bodies? Well, to optimize its replication, HIV is best-suited to the warm, moist, and dark environments inside our bodies.

• Temperature: If too cold, the HIV becomes dormant and inactive; when the temperature heats up, HIV is killed by the heat, as the proteins breakdown.
• Acidity levels: HIV survives best in our bodies’ neutral pH (7). If the environment becomes too acidic, the virus will become inactive and eventually inert.
• Environmental humidity: All lifeforms need water to survive, even HIV. When dried out, it destroys the component proteins.
• Sunlight: Ultraviolet light works as a disinfectant, destroying the HIV viruses.
• Amount of virus: The more viral particles in the fluid, the longer it takes for all of them to become inactive.

No matter the bodily fluids containing HIV, the time it can survive outside the body remains the same. As soon as it reaches the air and sunlight, viral particles begin to become inactive and inert.

• Blood: When a blood sample is taken, the remaining blood in the syringe can still transmit the virus. Inside the syringe, the viruses aren’t exposed to the air, allowing them to stay active for longer. That’s why sharing needles carries a high risk of infection. If the conditions are right, HIV may remain active for as long as 42 days – though this may require some refrigeration.
• Semen, vaginal fluids, rectal fluids, and breast milk: None of these bodily secretions has any special effect on HIV. The virus should become inert within a few hours after exposure to the air.
• Water: In one study, only 10% of HIV remained active after 1 to 2 hours in tap water; after 8 hours, only 0.1% remained.

The risk of HIV infection from outside body sources is negligible to non-existent. By far, the bigger risk is from unprotected anal, vaginal, and oral sex or from sharing needles. Blood transfusion also carries a minimal risk, as the blood is typically checked beforehand.

Nevertheless, if you come into contact with contaminated fluids, you can still seek post-exposure prophylaxis or regular HIV testing to ensure you remain HIV-free. Speak to our physician for further details.