http://www.nature.com/news/2007/070219/full/070219-8.html

Drugs that fight genital herpes also significantly reduce levels of human immunodeficiency virus (HIV) in patients infected with both viruses, a new study finds. Most HIV-positive patients also carry the herpes simplex virus, so anti-herpes drugs might help to restrict the spread of HIV.

The study, published in the New England Journal of Medicine this week1, highlights the importance of testing HIV patients for genital herpes - an infection that causes periodic genital ulcers but can lurk silently in the body for years.

Nicolas Nagot of the London School of Hygiene and Tropical Medicine in the United Kingdom and his colleagues conducted a clinical trial of 136 African women infected with both HIV-1 and the most common form of herpes simplex virus. Half the patients were given valacyclovir, a common herpes treatment; the other half received a placebo.

Women taking the drug had 70% lower levels of HIV in their plasma, and 50% lower levels of the virus in their genitals compared with those who received the placebo. Longer treatments could produce even better results, says Nagot, because HIV loads declined steadily through to the end of the three-month study.