If you’ve come into contact with some blood or other body fluid that you think might contain HIV, it’s understandable to have some concern about the possibility of HIV transmission. Fears over the casual transmission of HIV have also led many people to be concerned over the risk of contact with spilled blood, dried blood or other body fluids, even in microscopic quantities.
But what’s the truth? Can you get HIV with contact outside of the body?
While HIV may live for some time outside the body, HIV transmission has not been reported from contact with spillages of blood, semen or other body fluids, although many healthcare workers do come into contact with HIV-infected body fluids.
According to AIDS.gov, laboratory studies which have looked at the survival of HIV have found that:
HIV is sensitive to high temperatures but not to extreme cold. Experiments have shown that HIV is killed by heat, but temperatures over 60°C are needed to achieve reliable killing of HIV.
Levels of virus remain relatively stable in blood at room temperature, and HIV may persist for at least a week in dried blood at 4°C. Blood containing HIV used for laboratory experiments is stored at –70°C without any loss of viral activity.
HIV may survive in dried blood at room temperature for up to five or six days provided that the optimum pH level is maintained; drying of blood does not seem to affect the infectivity of HIV.
Leftover Medical Equipment
HIV may survive for up to four weeks in syringes after HIV-infected blood has been drawn up into the syringe and then flushed out.3 A study of blood gathered from more than 800 syringes filled with small amounts of HIV-infected blood and stored for various periods found that HIV could be isolated from 10% of syringes after eleven days where the quantity of blood was less than 2µl, but 53% of syringes where the quantity of blood was 20µl. Longer survival of HIV was also associated with lower storage temperature (less than 4°C); at higher temperatures (27 to 37°C) survival was not detected beyond seven days.
HIV is very sensitive to changes in alkalinity or acidity – pH level – and pH levels below 7 or above 8 are unsuitable for long-term survival of HIV. One reason why HIV transmission may be less likely in healthy women is due to the acidity of vaginal secretions.
Sewage is highly unlikely to pose a risk because infectious HIV has never been isolated from feces or urine. However,…