Herpes Treatment Could Help Keep HIV at Bay

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All of this suggests that interventions that control HSV might also help control HIV.

Nagot's team conducted a randomized, double-blinded, placebo-controlled trial involving 140 women from the West African nation of Burkina Faso, all of whom tested positive for both HIV, the virus that causes AIDS, and HSV-2, the herpes strain most often linked to genital infection.

The patients -- who were for various reasons ineligible for antiretroviral HIV-suppressing drugs at the time of the study -- received either 500 milligrams of HSV-suppressing Valtrex twice daily or a placebo for 12 weeks. The researchers then tracked the women for three months of follow-up.

They found that use of Valtrex cut down the amount of time HIV was highly present and active in the genital tract -- "shedding" -- by 59 percent, on average, and significantly reduced HIV viral load -- both within the female genital tract and in the bloodstream.

For the first time, the study proves in a clinical setting, "that HIV replication is causally related (at least in part) to HSV replication; and we have demonstrated that this replication can be reduced (in the genital fluids and plasma) with an antiviral therapy that is only directed at HSV-2," said study senior researcher Dr. Philippe Mayaud, also of the London School of Hygiene and Tropical Medicine.

Herpes treatment could never offer full protection against HIV, the researchers stressed. However, by lowering levels of HIV within the genital tract, it may reduce sexual transmission of the virus.

Furthermore, by lowering blood levels of HIV, herpes treatment should bolster patients' immune systems and thus "prolong the time until [they] need to start antiretroviral therapy," Mayaud said.

Valtrex, which remains under patent to maker GlaxoSmithKline, might still be too expensive for widespread use in developing countries. But the study's authors said another generic drug, acyclovir, is showing similar promise and is much cheaper.

The Burkina Faso trial was too short to show any Valtrex-linked reductions in HIV-related symptoms or illness in the women, Mayaud said. "The logical next step is to study the effect of acyclovir or valcyclovir over a longer duration, to study the impact on HIV-related outcomes linked to disease progression, like the decline in CD4 [T-cell] counts," he said.