How Long Can HIV Live Outside of the Body?

HIV can live outside of the body for several hours and, under the right condition, for several days. But this doesn't mean you can get HIV by coming into contact with semen, blood, or other bodily fluids on a toilet seat, toothbrush, countertop, or even discarded needle. To date, there have been no documented cases of HIV transmission by these means.

This article explains how long HIV can survive outside of the body, including the conditions in which the virus can persist. It also looks at what's required for HIV infection to take place and why it is unlikely—if not impossible—to get HIV once it leaves the body.

4 Conditions HIV Needs to Survive

HIV often dies within minutes of leaving the body. This is because the outer shell of the virus (called the viral envelope) consists of two layers of lipid (fat) molecules that are vulnerable to heat, UV radiation, and other environmental elements.

With that said, HIV can survive outside of the body for longer periods if specific conditions are met:

• Colder temperatures: Temperatures below 39 degrees F are ideal for HIV. HIV does not do well at room temperature (68 degrees F) and is even less viable at body temperature (98.6 degrees F).
• Neutral pH: HIV thrives when pH levels are neutral, around 7.0. The virus cannot survive for very long at pH levels below 7.0 (considered acidic) or above 8.0 (considered alkaline).
• UV exposure: Ultraviolet (UV) radiation quickly degrades the viral envelope of HIV. Even if the virus were to survive, any damage to the lipid shell would make it incapable of attaching to cells to infect.
• Dried blood: HIV can survive in dried blood at room temperature for up to six days. However, the concentration of viruses in dried blood is almost always low, and the viruses themselves would be damaged and nonviable for infection.
  

It is technically possible for HIV to survive outside of the body under these circumstances. Still, the risk of infection is at best unlikely.

4 Conditions Needed for HIV to Infect

Under the right conditions, HIV can survive outside of the body for up to six days.

But even if that were to occur, the odds of infection remain low to nil. This is because there are four conditions that must be met in order for an HIV infection to take place:

1. There must be body fluids in which HIV can thrive. This includes semen, blood, vaginal fluid, and breast milk. HIV cannot thrive in highly acidic or saline fluids, such as sweat and urine.
2. There must be a route for HIV to enter the body. The most effective means of transmission are vaginal sex, anal sex, and shared needles. Less commonly, HIV is passed from mother to child during pregnancy or through occupational exposure to HIV in hospitals.
3. The virus must be able to reach vulnerable cells inside the body. HIV cannot pass through intact skin. For HIV to establish an infection, you would need to penetrate deeper tissues. Scrapes and abrasions are not deep enough for the virus to establish an infection.
4. There must be enough virus in the body fluids. Many HIV exposures are neutralized by frontline immune cells called monocytes. When an infection occurs, it is usually because the quantity of HIV overwhelms these frontline defenders. (A handful of viruses in dried blood is unlikely to pose any threat to the body's immune defenses.)

Unless all four of these conditions are satisfied, an HIV infection simply cannot occur.

Perceived vs. Actual Risk

There is often a big difference between what a person perceives their risk of HIV to be and what their actual risk is.

Perceived risk is an individual's subjective evaluation of the risk of an illness. It is based either on a person's belief regardless of the facts or a person's interpretation of the facts. The perception can persist even though an event is unlikely.

By contrast, documented risk is an evaluation of risk based on available data. It is not meant to suggest that the data is infallible, but the longer a disease is tracked and studied, the stronger the evidence is.

After more than 35 years of HIV research, the likely and unlikely routes of infection are well-established. Even so, there are many who still question whether the unlikely routes are still possible. Such is the case with HIV and the risk of infection from needlestick injuries, body art, and oral sex.

Here is what the current research says:

• Needlestick injuries: In theory, you can get HIV from accidentally jabbing yourself with a needle found in a field. In 2018, an evaluation of available data concluded that not one case of HIV occurred following contact with a discarded needle.
• Body art: In theory, you can get HIV from tattooing or piercing if the equipment has been contaminated with another client's blood. According to the Centers for Disease Control and Prevention (CDC), there has not been one documented case of HIV by this means.
• Oral sex: In theory, you can get HIV from oral sex because there is a lot of HIV in semen. A 2016 study from the University of California, Irving concluded that the risk of HIV from oral sex is negligible.
  

How to Prevent HIV After the Fact

If in doubt as to whether you've been exposed to HIV, err on the side of caution and go to your nearest emergency room or walk-in clinic. The healthcare provider on site can tell you what your actual risk of infection is and offer you preventive treatment if there is any reasonable chance of exposure.

This involves a 28-day course of medications called HIV post-exposure prophylaxis (PEP). By taking the drugs every day as prescribed, you may be able to avert the infection. With that said, PEP needs to be started within 24 to 48 hours of exposure. After 72 hours, the treatment will be far less effective.

If your fear of infection is unreasonable and interfering with your quality of life, consider meeting with an HIV specialist to get the facts about HIV. You can also meet with a psychologist or psychiatrist who can address your anxieties and offer therapy and medications if needed.

Summary

HIV can live outside of the body for hours or longer if the conditions are right. This includes having cooler temperatures, avoiding UV radiation from the sun, and being in an environment that is neither too acidic nor too alkaline.

Even if HIV manages to survive in these conditions, the chances of infection are low to nil. This is because HIV infections occur when ample quantities of the virus are able to access deeper tissues of the body.

To date, there is no documented evidence of anyone getting HIV from surfaces or objects that have been contaminated with semen, blood, or other body fluids. This includes getting HIV from discarded needles.

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