Treating genital herpes does not reduce eisk of HIV

Jun 24 2008

Treating genital herpes does not reduce the risk of HIV, according to a study published on Friday in the journal Lancet, the AP/Newsweek reports (Cheng, AP/Newsweek, 6/19). Herpes simplex virus-2 has been shown to increase the risk of HIV by as much as threefold, so the researchers examined whether treating HSV-2 might reduce the risk of HIV, Bloomberg reports.

For the study, Connie Celum of the University of Washington-Seattle and colleagues enrolled 3,172 men and women in Africa, Peru and the U.S. (Britt, Bloomberg, 6/20). All the participants were HIV-negative and HSV-2-positive at the start of the study. The researchers enrolled participants who had similar HIV/AIDS risk levels, and the participants were questioned monthly about risky sexual behavior with recent partners.

About 50% of the participants were given aciclovir, a drug that can suppress outbreaks of HSV-2, and half were given a placebo. The study -- funded by NIH's National Institute of Allergy and Infectious Diseases, GlaxoSmithKline and other government agencies -- found that the participants given aciclovir were not less likely to contract HIV than those given placebos. The study found that after a year-and-a-half, 75 people out of the 1,581 participants who received the drug contracted HIV, compared with 64 in the placebo group (AP/Newsweek, 6/19). In addition, the researchers found that aciclovir reduced genital ulcers by 47% and genital ulcers linked with HSV-2 by 63%.

"Our results show that suppressive therapy with standard doses of aciclovir is not effective in reduction of HIV-1 acquisition," Celum said, adding, "Novel strategies are needed to interrupt interactions between HSV-2 and HIV-1." Researchers need to determine why the drug failed to reduce the risk of HIV and did not reduce genital ulcers as much as expected, Celum noted. She said that it might be because the drug is not absorbed well or because it is metabolized too quickly (Bloomberg, 6/20). According to the AP/Newsweek, the study's findings do not "necessarily mean that the theory of treating herpes to avoid HIV is incorrect," according to researchers. "It's probably likely that we need considerably more potent interventions than we have," Celum said.

Francis Ndowa -- coordinator of the sexually transmitted infections control team at the World Health Organization who was not a part of the study -- said, "It's a significant, disappointing finding." He added that it was possible that even without ulcers, herpes might have lingered while the participants were taking aciclovir, increasing the risk of HIV. Both Ndowa and Celum said the strategy of fighting herpes to prevent HIV transmission might work if different doses or a more powerful drug were tried. However, Ronald Gray and Maria Wawer of Johns Hopkins University in an accompanying commentary questioned whether controlling other STIs can help curb the spread of HIV. They wrote, "It is time to reassess the hypothesis and to adjust [HIV] prevention policy accordingly" (AP/Newsweek, 6/19).

The study is available online. The commentary also is available online.