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How long can HIV live outside the body?

How long can HIV live outside the body?

  • HIV can survive outside the body for weeks

  • There has never been a case of HIV infection from casual contact with contaminated surfaces of potentially infected body fluids

I often get this question or variations on it for example:

How long can HIV survive in air?

How long can HIV survive on surfaces?

Let’s look at the evidence available to us.

  • HIV is killed by heat. Temperatures of above 60⁰C will kill HIV.
  • HIV is NOT killed by cold. In fact, colder temperatures increase the survival time of HIV.
    • At 27⁰C to 37⁰C, HIV can survive up to 7 days in syringes
    • At room temperature, HIV can survive in dried blood for 5 to 6 days
    • At 4⁰C, HIV can survive up to 7 days in dried blood
    • At -70⁰C, HIV can survive indefinitely
    • HIV can only survive in pH between 7 and 8
    • HIV has been found to survive for a few days in sewage
    • HIV has been found to survive in organs and corpses for up to 2 weeks

You would notice that all these studies are done on blood. There is really no good evidence to determine how long HIV from semen, vaginal secretions of other body fluids can survive outside the body. One fact is that it is very difficult to culture HIV from semen. This indicates the low viral content and we can assume that the same timelines for blood apply to semen if not less.

In these experiments, the survivability of the HIV virus is determined by its retention of the ability to infect cells in cell culture.

We must be careful not to equate survivability to infection.

In other words:

  • HIV infected surface/fluid + broken skin ≠ HIV infection

This is because there are many other factors that influence infection for example, the amount of virus has to be high enough in order to cause an infection. Also, when live HIV virus comes into contact with broken skin or mucosa, it still has to undergo a very complex series of steps before it actually causes a HIV infection. The mechanism of HIV infection is a lot more complex and will be discussed in detail in another article.

You would also note that these experiments were all done in a controlled environment of a lab. Many other factors such as wind, rain, humidity, type of surface etc are not taken into account. Most people ask this question because they have been exposed to some potentially infected fluids and are afraid of being infected with HIV.

To date, there have not been any cases of HIV transmission via casual contact with surfaces or contaminated fluids. HIV is transmitted via sexual intercourse, blood transfusion and sharing of infected needles. There have also been isolated cases of HIV transmission from dental treatments.

In summary, if you have touched some surface or fluid that you think might be contaminated with HIV, do not worry. You will not get infected. If you had a high risk exposure to HIV within the past 72 hours, you can take medicines to reduce your risk of actually contracting HIV.