A drug prescribed for the prevention and treatment of HIV may also help reduce the risk of contacting herpes simplex virus type 2, according to a new research report.

The study, published Tuesday by researchers at the University of Washington, focused on heterosexual males and females living in Kenya and Uganda who are at high risk for HIV given a partner infected with HIV.

The drug, Tenofovir for HIV-1 preexposure prophylaxis, also known as Truvada, "significantly reduces the risk for herpes (HSV-2), states the study, published in the July issue of Annals of Internal Medicine.

"Modest protection against HSV-2 is an added benefit of HIV-1 prevention with oral tenofovir-based PrEP," state the authors.

Use of the drug reduced the risk of getting genital herpes by 30 percent, yet the findings are not enough to have doctors prescribe tenofovirus as purely a herpes preventative drug due to its high cost. The cost of the tenofovir drug is $100 a year in Africa and $1,000 per month in the United States, according to the research team.

"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.

The study's lead author, Dr. Connie Celum, director of the International Clinical Research Center at the University of Washington, said, "it is beneficial that oral tenofovir can reduce the risk of acquiring genital herpes as well as HIV."

Earlier research has indicated that Truvada, when used with other preventative HIV measures, can cut HIV transmission by nearly 90 percent. According to health officials HIV and herpes infections very often occur together.

Herpes simplex 2 is a common cause of genital herpes. Herpes simplex 1 is another type that commonly causes cold sores.

The latest study involved 1,500 adults who were monitored between 2008 and 2010.

"About 20 percent of adults in the U.S. have genital herpes infection, and about 50 percent of adults in Africa," said Celum. "Previous studies have indicated that genital herpes increases the risk of becoming HIV-infected by about two-fold."