Valtrex Lowers Herpes Transmission
Drug May Prevent Spread of This Incurable STD
Sept. 27, 2002 -- The drug Valtrex -- prescribed to prevent recurrences of genital herpes -- may actually help prevent the spread of the virus from one sexual partner to another.
The lifelong infection affects 1 in 5 adults, and many infected people don't have symptoms and don't know they are infected.
In the study heterosexual, monogamous couples were instructed to use condoms during sex. Previous research has shown that even when told to use condoms, many monogamous couples don't follow these instructions.
Once-daily Valtrex cut the chance of the partner getting herpes with no symptoms by 50%. The risk of developing genital herpes with symptoms in the partner dropped by 77%.
"This is the first time that a drug has been shown effective against the transmission of virally transmitted infections," lead researcher Larry Corey, MD, tells WebMD.
Corey is professor of laboratory medicine and medicine at the University of Washington and head of infectious diseases at the Fred Hutchinson Cancer Research Center in Seattle. He presented his findings today at a meeting of infection disease specialists in San Diego.
"This is a breakthrough concept," he says. "It could offer a means of managing other sexually transmitted diseases.
"Condoms have been only partially effective in preventing transmission," says Corey. "It could be that most monogamous couples use condoms for contraception rather than to prevent transmission of infection. So condoms aren't necessarily always put on in the really early stages of the sexual event. That may be a factor for herpes. In that case, other approaches of prevention are necessary."
Surveys over the years have shown that one of the major concerns most people have is transmitting genital herpes to a sex partner. "We now have a drug that for the first time allows a person to use medication as one form of decreasing transmission," he says.
Because the couples were asked to use condoms every time the had sex, some of the reduction in transmission may be due to condom use, not Valtrex alone.
Corey's study was conducted in 126 sites on four continents. Researchers identified more than 1,400 couples in which one had genital herpes and one did not. In half the couples, the person with herpes got Valtrex; in the other half, the infected person got a placebo. During the eight-month study period, the other partner was then monitored to find out if they had become infected.
The findings are "pretty convincing," Clyde Crumpacker, MD, an infectious disease specialist with Boston's Beth Israel Deaconess Medical Center and professor of medicine at Harvard Medical School, tells WebMD.
"I think it's the first time this has been tested in a study as rigorous as this," says Crumpacker, who agreed to review the study for WebMD.