HIV Virus Survival

Dear Ask The Doctor: I have been reading on different health forums on the internet that the HIV virus is quite fragile and that it dies quickly outside its host body. My questions are: 1. Does the virus die as soon as the blood sample is drawn from one's body and is kept in a test tube? 2. If it dies so quickly, how a lab test is performed? 3. Why is it possible to contract HIV through donated blood (that is infected)? Thanks

Dear Creative:HIV is transmitted when the virus enters the body, usually by injecting infected (needle stick) cells or semen. There are several possible ways in which the virus can enter: Most commonly, HIV infection is spread by having sex with an infected partner and the virus can enter the body through the lining of the vagina, vulva, penis, rectum, or mouth during sex. HIV frequently spreads among injection-drug users who share needles or syringes that are contaminated with blood from an infected person. Women can transmit HIV to their babies during pregnancy or birth, when infected maternal cells enter the baby's circulation.  Nowadays is very rare that HIV spreads through transfusion of contaminated blood or blood components. Blood products are now tested to minimize this risk. If tissues or organs from an infected person are transplanted, the recipient may acquire HIV. Donors are now tested for HIV to minimize this risk.

Yes, the HIV virus is very fragile when outside the human body, but remember that the blood contains “cells”, red blood cells which can harbor the virus for a while. In the tests it is not the virus itself what is detected but the response of the body to it, by radioimmunoassay techniques. HIV infection is commonly diagnosed by blood tests that detect antibodies the immune system produces in an attempt to fight the virus. Testing for HIV is a two-step process: first, an inexpensive screening test (blood) or oral (saliva) is done. If that test is positive, a second test (Western blot) is done to confirm the result.