I've read that HIV can only survive outside the body for a few minutes...how long does it survive inside a needle though?
Hope you can answer
Several variables will effect the length of survival/viability of HIV in a syringe or hollow-bore needle. The volume of blood in the needle, the HIV titer (or the amount of virus in the blood), and temperatures the needle is exposed to will have significant effects on HIV's viability. Volume of blood in the needle is partially dependent on the size of the needle's bore and how the needle is used (is blood drawn into the bore or is it used for injection only?).
One study that stored needles containing high-titer HIV-1-infected blood at constant temperatures found that viable HIV could be isolated in the blood samples up to 48 days. Viability clearly decreases over time; in some samples, viable HIV was only isolated in 26% of the syringes after 2-10 days elapsed. There was a strong association between high volume of blood and the ability to isolate viable HIV. Lower storage temperatures were also strongly associated with longer HIV viability. Low viral titers, changes in temperature or high temperature, and lower volumes of blood will rapidly decrease HIV's viability.
Important note: laboratory studies do not always translate well into the realities of day-to-day life. Syringes used in a person's environment, whether they are used by healthcare workers or injection drug users, will not mimic the criteria of a controlled laboratory study. Very specific conditions need to be met for HIV to survive within a needle.
This issue is of greatest importance to injection drug users (IDUs). For prevention purposes, it should be assumed that a syringe should never be shared (unless it is sterilized) because it can remain contaminated up to 48 days, and maybe longer. This is an extremely important argument for availability and access to clean syringes and education on sterilizing needles for IDUs.