Research led by a team of Seattle scientists has concluded that people with genital herpes can reduce their sex partners' risk of contracting the disease by taking a daily pill. The results were published Thursday in the New England Journal of Medicine. "For the first time, we were able to interrupt the transmission of viral disease," said Dr. Lawrence Corey, head of both the infectious diseases program at Seattle's Fred Hutchinson Cancer Research Center and the virology program at the University of Washington. The finding showed the drug valacyclovir, sold under the brand name Valtrex, cut transmission of genital herpes by 48 percent. "This gives you the (means) to do something medically about it," said Corey, the lead investigator for the research team. "Both patients and providers should be aware of the implications of this study." Genital herpes is a silent but stubborn epidemic. The sexually transmitted virus infects an estimated one in five Americans over age 12, according to the U.S. Centers for Disease Control and Prevention . As many as 90 percent of those who are infected don't know it because most people with the virus have mild or no symptoms. It's a serious public-health issue because the disease is incurable, and herpes sores on the genitals can be painful and facilitate the transmission of HIV, the virus that causes AIDS. Corey said this is the first time an anti-viral drug has been shown to thwart the spread of a sexually transmitted disease. The pill is a major boon for herpes patients because their greatest concern is spreading the disease to a partner, Corey said. Preliminary results from the study helped GlaxoSmithKline win federal approval for use of valacyclovir to prevent sexual transmission of genital herpes. The study followed nearly 1,500 heterosexual, monogamous couples for eight months in the United States, Canada, Europe, South America and Australia. In each case, one partner had genital herpes and the other did not. Half of the infected people were given a daily dose of Valtrex and the other half received a placebo. Both groups were urged to use condoms, but few did so consistently. The chance of spreading herpes to a partner was low during the eight-month study, even among the placebo group, perhaps because these were established partners who'd already managed to avoid passing the virus. The likelihood of passing herpes to a partner was 3.6 percent without Valtrex compared with 1.9 percent with the drug. The drug is not 100 percent effective at preventing transmission, so people with herpes should still tell potential partners about their infection, said Dr. Anna Wald, medical director of the UW Virology Research Clinic and co-author of the study. Using a condom also can help reduce transmission, by as much as 50 percent in some studies, she said, as can avoiding sexual intercourse during an outbreak of blisters. The Valtrex pill can cause headaches, nausea and kidney problems. GlaxoSmithKline, which sells the pill for about $3.50 per day wholesale, sponsored the study. Dr. Connie Celum, a professor of medicine at UW, said more than 30 studies around the world show a link between genital herpes and HIV acquisition and transmission. Up to 80 percent of HIV-infected people in some areas of sub-Saharan Africa also have herpes, Celum said. | 
