"These results should provide relief to hundreds of thousands of HIV-positive patients in the United States currently taking drug therapy, called highly active anti-retroviral therapy, or HAART, and reassure them that their medications have not failed," says senior study author and infectious disease specialist Robert Siliciano, M.D., Ph.D., a professor at The Johns Hopkins University School of Medicine and a Howard Hughes Medical Institute investigator. "Physicians and patients now have a much better idea of when to worry about these blips and when not to worry."

Because HIV mutates very rapidly, physicians and patients have worried that even small, temporary increases in the amount of virus could indicate the virus had mutated to evade anti-viral drugs being taken.

Instead, the Hopkins team has shown that these so-called blips are mathematical artifacts, or variations, that stem from the test used to gauge the amount of virus in the body, a measurement known as viral load.

According to the Hopkins findings, to be published in the Journal of the American Medical Association online Feb. 16, unless the blip is higher than 200 copies per milliliter of blood, or persists upon repeated testing, it does not signal that the virus has mutated, or changed form.

True drug resistance requires changes in therapy which can be very difficult for the patient, says Siliciano. Different combinations of medications can have toxic side effects, such as lipid abnormalities and diabetes, and can be considerably harder to tolerate than the originally prescribed drug cocktail. Today's anti-HIV drug treatments quickly suppress the virus to nearly undetectable levels, but blips are a frequent problem. Earli
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Contact: David March
dmarch1@jhmi.edu
410-955-1534
Johns Hopkins Medical Institutions
15-Feb-2005