PHILADELPHIA -- Women who have sexual relationships with men suffering from genital herpes run a high risk of contracting the incurable disease themselves, even if the man has no symptoms, a new study says.
The findings, reported today in the journal Annals of Internal Medicine, based in Philadelphia, provide a chilling warning to both women and men who think they can avoid the disease by having sex only with those who do not have visible herpes sores.
And there is little protection in having sex only with men or women who say they do not have herpes because 80 percent of genital herpes carriers do not know they have the disease, said the study's lead author, Gregory Mertz of the University of New Mexico. About half have never had symptoms, he said.
The study, conducted at the University of New Mexico and the University of Washington in Seattle, followed 144 heterosexual couples -- one partner with genital herpes, the other without -- for nearly a year.
During that time, the couples faithfully recorded every instance of sexual intercourse and every herpes outbreak.
The researchers found that:
* Nearly 10 percent of the uninfected partners caught genital herpes even if they avoided having sex during the painful outbreaks of blisters and rashes; they apparently contracted the disease from the invisible "shedding" of the herpes virus that occurs around lesion sites.
* Women partners were four times more likely to contract genital herpes from male partners than men were to contract it from women. The finding is consistent with previous research that has shown that women are more vulnerable to sexually transmitted diseases, Dr. Mertz said, "probably because they have mucous membranes in the vagina and cervix which are exposed during sexual contact."
* Only one couple routinely using condoms experienced transmission of the disease.