Herpes drug Acyclovir does not reduce risk of HIV transmission, does slow HIV progression, study says

May 14 2009

The drug acyclovir, which suppresses herpes simplex virus-2, does not reduce the risk of HIV transmission when taken by HIV-positive people who also have herpes, according to a study conducted by researchers at the University of Washington, United Press International reports.

According to United Press International, genital ulcers associated with HSV-2 are known to increase the risk of HIV transmission.

The study was conducted among 3,408 discordant couples, in which one member is HIV-positive and the other is not, at 14 sites in seven African countries: Botswana, Kenya, Rwanda, South Africa, Tanzania, Uganda and Zambia. The primary results of the study found that 41 new HIV cases occurred in the couples in which the HIV-positive member took acyclovir, compared with 43 new infections among the couples who did not take the drug. The results were not statistically significant, according to the researchers (United Press International, 5/13). However, the study did find that acyclovir can slow progression of HIV by 17% in HIV-positive people who also have HSV-2 and whose CD4+ T cell counts are too high to begin antiretroviral therapy.

"Although the primary outcome of reducing HIV transmission was not observed, the study yielded important information that will inform HIV prevention research in a number of ways," Connie Celum, a professor of global health and medicine at the University of Washington's Division of Allergy and Infectious Diseases, said. She added that the "findings will bear fruit for both the HIV prevention and vaccine fields for years to come."

The study, called the Partners in Prevention HSV/HIV Transmission Study, was funded by the Bill & Melinda Gates Foundation (University of Washington release, 5/8).