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
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.
Those results aren't strong enough to warrant the use of tenofovir alone or in combination solely for herpes prevention, according to Cohen. He added that tenofovir "is not designed to reduce herpes acquisition."
So why does it matter if tenofovir prevents genital herpes? Because it's a very common infection and can pave the way for other medical problems.
"About 20 percent of adults in the U.S. have genital herpes infection, and about 50 percent of adults in Africa," study lead author Celum said. "Previous studies have indicated that genital herpes increases the risk of becoming HIV-infected by about two-fold."
The cost of the tenofovir combination drug is about $100 a year in Africa and $1,000 per month in the United States, she said.
The next step for research is to determine if tenofovir can provide protection against HIV and herpes when administered through vaginal and rectal gel and in a vaginal ring, she said. Researchers also want to know if the drug can prevent people with HIV from getting herpes.
As for cold sores -- herpes simplex virus 1 -- she said tenofovir may have an effect on it, too. Previous research using tenofovir in a vaginal gel reduced the risk of both herpes simplex 1 and 2.
The study is in the July 1 issue of the Annals of Internal Medicine.