New Warning Issued on Spread of Herpes

Researchers at the University of Washington in Seattle and the University of New Mexico at Albuquerque have found stronger evidence that genital herpes can be sexually transmitted even when there are no signs of the painful blisters that are the hallmark of the disease.

The one-year study of 144 heterosexual couples also confirmed that a woman is at higher risk of acquiring the viral infection from an infected man than the other way around.

The researchers were led by Dr. Gregory J. Mertz of the University of New Mexico and Dr. Lawrence Corey of the University of Washington.

The researchers said their study, published today in the Annals of Internal Medicine, was the first to follow couples in which one member had recurrent herpes and the other was not infected. Most previous studies of herpes infections have tried to backtrack to the circumstances of the infection after it had already occurred.

An estimated 30 million Americans are believed to have had at least one episode of genital herpes. The infection causes painful blisters on the skin and moist lining of the sex organs of men and women. The drug acyclovir can be used to shorten the duration of pain and the release of viruses from the blisters. Some infected people have frequent recurrences, which may last about a week.

Physicians recommend that infected people not have sex during outbreaks and that condoms be used to reduce the risk of transmission during asymptomatic periods.

The researchers found 14 instances of genital herpes transmission, 11 from men to women and three from women to men. Most of the transmission occurred in couples who were not using barrier contraception, such as a diaphragm or condom.

In nine couples, transmission appeared to occur while the infected partner had no herpes symptoms. In three couples, transmission appeared to result from sexual contact hours before the blisters were first noticed by the infected partner, according to the study.