UW News

June 26, 2001

Greater condom use could help prevent spread of genital herpes

Condom use helps to prevent the spread of genital herpes, particularly from a man with HSV-2 to a susceptible woman, according to a study in the upcoming issue of the Journal of the American Medical Association. Condom use might help slow the epidemic of genital herpes, which now infects about one in five Americans.

“This study is the first to document protection against HSV-2 acquisition through the use of condoms. Couples should take this into account: A partner with herpes can decrease the risk of giving herpes to their partner by using a condom,” says Dr. Anna Wald, director of the University of Washington Virology Research Clinic and an assistant professor of allergy and infectious diseases in the UW School of Medicine and of epidemiology in the School of Public Health and Community Medicine.

In the United States, about half a million people — 350,000 women and 150,000 men — acquire genital herpes (HSV-2) every year.

“Our analysis suggests that more consistent condom use could avert up to 315,000 new cases of HSV-2 infection among women,” Wald says. “Unfortunately, condom use remains infrequent in the general population.”

The findings of Wald and colleagues will be published in the June 27 issue of JAMA. Other authors of “Effect of Condoms on reducing the transmission of Herpes Simplex Virus Type-2 from Men to Women” include Dr. Lawrence Corey, the head of both the Fred Hutchinson Cancer Research Center Clinical Research Division’s Program in Infectious Diseases and the Virology Division at the UW Department of Laboratory Medicine; Dr. Rhoda Ashley and Katherine Link of UW Department of Laboratory Medicine; Dr. Andria Langenberg and Allen E. Izu of Chiron Corp., Terri Warren of Westover Heights Clinic, Portland; Dr. Stephen Tyring of the University of Texas, Galveston; and Dr. John M. Douglas Jr., Department of Public Health, Denver.

Genital herpes is caused by a virus that enters the body through tiny breaks in the skin. It is spread by contact with infected secretions during sexual encounters. The JAMA study found that women were six times more likely than men to get infected per sex act. The rate of infections is 8.9 infections per 10,000 sex acts for women, and 1.5 per 10,000 for men. This is similar to the rate of infection seen in sexually acquired HIV.

An estimated one in five people in the United States has genital herpes, though most do not know it because they do not have symptoms or think its mild symptoms are caused by something else. Because of new tests, more and more Americans are learning that they have genital herpes. Before, it had been difficult to diagnose HSV-2 because older blood tests confuse it with herpes type 1, which usually causes cold sores.

Before this study, it was not known for sure if condom use would prevent HSV infection. While condoms are known to protect against STDs in general, there was some concern that they might not be helpful against herpes because herpes is shed over a large area of the genital region.

Wald and colleagues studied more than 500 couples who participated in a study of a vaccine that did not work. However, the study allowed the scientists to look at how well condoms protected people from acquiring herpes. The participants kept a diary of sexual acts and condom use. Condom use was not frequent, even among those who were given counseling about the use of condoms. Of 304 couples that reported they used condoms at times, only 13 percent used condoms for each sex act and 49 percent used condoms less than once per four sex acts.

Of the 118 people who used condoms more than half the time, only two became infected with HSV-2. Of 20 other people who were infected, half reported that they never used a condom. An analysis of the data showed a connection between condom habits and reduced risk of infection for women. The study did not find that condoms protected men from acquiring the infection. However, very few men in this study acquired genital herpes, which makes it difficult to draw conclusions about the risk.

Genital herpes has no cure, but can be treated with medication. Herpes can be dangerous because herpes sores allow easier transmission of HIV. And genital herpes can have serious ramifications during pregnancy. The baby can become infected while passing through the birth canal. Because a baby’s immune system is not fully developed, an infection can be fatal or result in permanent brain damage.

People interested in participating in studies relating to HSV-2 treatment, prevention, or vaccines can call the UW Virology Research Clinic at (206) 720-4340.