We have always been told that it is neccesary to keep on all all meds when on HAART to prevent hiv be coming resistant. However i have been curious to know what effect on viral resistance develops when the hiv virus may only be exposed to parts of the body , such as the brain, where not all meds are present. Does the virus then mutant because not all meds are to knock it down, and can this virus then reenter the bloodstream and devope resisant to the haart regimen?

Thank you for your question.

This is an area of great interest to researchers now. It is true that medications penetrtate to various parts of the body differently. The brain, genital track and intestines may have different levels of medication exposed to the virus. What seems to be true is that the amount of virus (viral load) in these various compartments of the body goes up and down pretty much together. That there may be blips in one area and not another also seems to be true, this has been shown in genital track secretions. But so far it has not been shown that virus in one of these compartments has developed resistance that could spread elsewhere. It seems that the longer the viral load is fully suppressed, the less likley it would be for resistant virus to emerge as long as the treatment is not interrupted. Studies are being done measuring viral levels in the fluid that surrounds the brain to measure the virus levels in relation to how well different medications penetrate into these fluids. This type of research may help us choose combinations that would have the best response over long periods of time, especially if people have memeory problems that might be related to HIV.

Thanks, Joe