(July 20, 2010 - Insidermedicine)

ndividuals who have participated in clinical trials for HIV vaccines may have false positive results if they are subsequently tested for HIV, according to research published in the Journal of the American Medical Association.

Here is some information about HIV and its treatment:

•    Currently, an estimated 7,500 people are being infected with the virus worldwide every day

•    The number of people gaining badly-needed access to HIV treatment is on the rise

•    At the end of 2009, approximately 5.2 million people in low- and middle-income countries were receiving life-saving treatment for HIV

Researches from Fred Hutchinson Cancer Research Center used several standard HIV testing kits to evaluate the HIV status of over 2,000 individuals who had participated in clinical trials for HIV vaccines in the previous decade. Several different vaccine types were tested during these trials. The results of the standard HIV tests were compared against more sophisticated and accurate tests known as Western blot analysis and nucleic acid testing.

Overall, nearly 42% of the participants tested positive for HIV on the standard tests when the more accurate tests showed that they were not, in fact, HIV-positive. The rates of these false positives varied widely – from under 10% to over 85% -- depending on what type of vaccine the participants had been exposed to. Each of the different HIV test kits used also gave different rates false positive results.

Today’s research indicates that individuals who participate in clinical trials for HIV vaccines should be followed up using more sophisticated testing to ensure they are not falsely identified as being HIV positive using standard tests.