HIV Prevention Drug May Lower Genital Herpes Risk
But effect isn't strong enough to make it a stand-alone preventive treatment for herpes, expert says
By Randy Dotinga
MONDAY, June 30, 2014 (HealthDay News) -- A combination drug used to treat and prevent HIV -- Truvada -- may have an additional benefit: lowering the risk of a genital herpes infection, a new study suggests.
Researchers found that African heterosexuals who were at risk of getting HIV from their partners were about 30 percent less likely to get infected with genital herpes if they took the drug tenofovir alone or with emtricitabine. Truvada is made from the combination of these two drugs.
The study isn't likely to lead physicians to use tenofovir -- alone or in combination with emtricitabine -- solely to prevent herpes, one infectious-disease specialist said.
"No one is going to use tenofovir specifically to reduce herpes. There are some side effects and the drug is not cheap. It will only be used as prevention for HIV -- not herpes -- for high-risk people," said Dr. Myron Cohen, associate vice chancellor for Global Health at the University of North Carolina School of Medicine in Chapel Hill, who's familiar with the new research.
Still, "it is beneficial that oral tenofovir can reduce the risk of acquiring genital herpes as well as HIV," said study lead author Dr. Connie Celum, director of the International Clinical Research Center at the University of Washington, especially considering that genital herpes boosts the risk of HIV infection.
Previous research from the U.S. Centers for Disease Control and Prevention has suggested that the use of Truvada, along with other preventive measures such as consistent condom use, can cut the risk of HIV transmission by as much as 90 percent.
The current study is part of research initially launched to gain a greater understanding of how tenofovir can be used to prevent HIV infection. HIV and herpes infections often occur together. And previous research suggested that a vaginal gel made with tenofovir could cut the risk of genital herpes by about 50 percent, according to background information in the new study.
That led the researchers to wonder if oral tenofovir alone or as part of Truvada could help prevent herpes infections, too.
The type of herpes the researchers looked for in this study was herpes simplex 2 (HSV). This type of herpes is a common cause of genital herpes, according to the CDC. Herpes simplex 1 is another type of herpes, and it commonly causes cold sores, according to the CDC.
The new study tracked almost 1,500 adults who randomly received tenofovir, tenofovir with the AIDS drug emtricitabine (Truvada), or a placebo. None of the study participants had HIV or herpes simplex 2 when the study began. Researchers monitored the participants from the initial enrollment period of 2008 to 2010, until 2011.
The risk of getting herpes simplex 2 was reduced by 24 percent for those taking tenofovir alone, and by 36 percent for those taking the Truvada combination, compared to those taking placebo.