Trial shows HSV-2 suppression can reduce HIV shedding

Almost a dozen clinical trials are now ongoing to see if drugs to suppress herpes simplex virus-2 (HSV-2) can reduce the risk of HIV transmission and infection (see VAX November 2005 Spotlight article, HIV prevention in a pill?). These studies were initiated because of mounting evidence that there is an association between HSV-2 and HIV infection. Researchers have long thought that HSV-2 infection could increase the amount of HIV in the genital tract and therefore increase both sexual transmission of and infection with HIV. But a relationship between these infections has not been firmly established in a controlled, clinical trial until now. At the 13th Conference on Retroviruses and Opportunistic Infections (CROI) held this February in the US, Nicolas Nagot from the London School of Hygiene and Tropical Medicine (LSHTM) in the UK in collaboration with the Centre Muraz in Bob-Dioulasso, Burkina Faso, presented data from the first "proof of concept" trial verifying the association between HSV-2 infection and HIV.

This study enrolled 140 women infected with both HIV and HSV-2 in Burkina Faso and randomly assigned them to either the treatment or placebo group. Those on treatment received the anti-herpes drug valacyclovir once a day for three months, while those in the placebo group received an inactive substance. The women were followed for a total of nine months, three months prior to and for three months following treatment. Over 12 visits, researchers measured the levels of HIV and HSV-2 in the genital tract of these women and found that those taking valacyclovir had significantly lower quantities of HIV than those that received placebo. Valacyclovir also significantly reduced the level of HSV-2 in the genital tract of women compared to those in the placebo group.

Although this study does not show a direct link between HSV-2 suppression and HIV transmission, this is the next step for researchers. Several trials are currently ongoing to see if HSV-2 suppressive therapy can lower HIV infection rates.

All articles written by Kristen Jill Kresge