There are many fears and misconceptions about HIV survivability and infection risk.
We often get asked some form of this question by people who have come into contact with potentially infected blood or bodily fluids from surfaces or other objects and who are worried about HIV infection risk.
Most importantly, there have been no validated cases of HIV transmission through casual touching of surfaces or objects (e.g. toilet seats, toothbrushes, towels) to date.
However, it is true that HIV has been shown to survive outside the human body for up to several weeks in certain environmental conditions.
How Long Can HIV Survive Outside the Body?
So what does the evidence say so far?
- At > 60⁰C – HIV is killed by heat temperatures of > 60⁰C are sufficient to kill HIV.
HIV is NOT killed by cold – It is known that the survival time of HIV increases in colder temperatures.
- At 27⁰C to 37⁰C, the HIV can survive for up to 7 days in syringes (fresh blood)
- At room temperature, the 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 without any loss of viral activity – this is the temperature that HIV-infected blood is stored at in laboratory experiments for future testing.
2) pH Level
- HIV can only survive in a narrow band of pH between 7 and 8
DID YOU KNOW:
- HIV has been found to survive for a few days in sewage in laboratory based experiments; however, it has not been detected in urine or stool samples in any real-life setting.
- HIV has been found to survive in organs and corpses for up to 2 weeks after death, especially in cooler temperatures.
- HIV has been found in low levels in breast milk, with infective transmission possible from mother to baby; however, no studies have been performed to determine how long it is infective once it is outside the body
Semen or vaginal fluids outside the body
There have been no studies on HIV survival in semen or vaginal fluids outside the body, but so far evidence indicates that it is only present at very low levels and is unlikely to pose a risk of infection from contaminated surfaces.
These studies have mainly looked at HIV survivability in laboratory based experiments, and have not taken into account the effect of environmental conditions such as wind, rain, and sun exposure. Further studies are needed to more clearly elucidate the risk of certain exposures.
Also, just because HIV can survive outside the body does not mean that it is necessarily infective. Even when live HIV virus comes into contact with broken skin or mucosa, it must still be present in an adequate dose to establish infection (the tissue culture infectious dose), and must then undergo a complex series of steps before it actually causes an HIV infection.
Survivability ≠ Infectivity
HIV transmission thus far has only been shown to occur through sexual intercourse, contaminated needles (including tattoos and body piercing), blood transfusions, and very isolated cases of dental procedures and eyesplash incidents with infected blood. There have been zero cases of infection from casual contact with a contaminated surface or object to date.
In a Nutshell
All in All, if you have touched some surface or fluid that you think may be contaminated with HIV, do not worry – you will not get infected.
However, it is still important to practice proper hygiene and infection control measures to reduce the risk of other infections as well.
If you believe you have had a potential high-risk exposure within the last 72 hours, you may consider Post-Exposure Prophylaxis (PEP) – this course of medication can greatly reduce the risk of HIV infection following an exposure. Please contact us for a consultation if you think you need PEP.
If you have any other questions or concerns, please visit our Doctor Moderated Online Forum on Sexual Health, HIV and STDs.
If you are interest to go for an Anonymous HIV Testing, please visit our Robertson Walk Branch.
We are Singapore MOH Approved Anonymous HIV Test site in Singapore.