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Herpes Spreads, Even Without Symptoms

According to doctors, even people without a clinical history of genital herpes can spread the virus to sexual partners.

You don't have to be in the middle of an outbreak to pass virus to sex partner

Most people with genital herpes, a sexually-transmitted viral infection, don't know they have it. And many who know they're infected mistakenly believe they can only pass the virus to their sex partners if they have genital lesions.

A new study finds transmission of the virus is much easier than that, and suggests that sexually active people should get tested for genital herpes. The disease not only has serious consequences for pregnant women, but can also make people more vulnerable to HIV, the virus that causes AIDS.


Ninety percent of American teenagers take classes on sexually-transmitted diseases by the time they graduate from high school. Yet despite that, the U.S. Centers for Disease Control reports that teens between the ages of 15 and 19 have higher rates of sexually-transmitted disease than any other age group.

Genital herpes is a disease that frequently goes undiagnosed. Most infected people are unaware they have the disease.

Doctors Anna Wald and Christine Johnston, from the University of Washington in Seattle, studied 500 people. Some had genital herpes. Others had never had a herpes outbreak, but they had antibodies for genital herpes, which is also called herpes simplex virus two, or HSV-2.

"This was the first study to look over time at people that have HSV-2 infection but don’t have a history of genital herpes," says Wald, "and we really did not know before this how often the virus is active in the genital tract of such persons."

The researchers examined swabs the volunteers took of their genital area daily for 30 days. The goal was to find out how often the virus was active.

"Many people think with genital herpes infections that they can only spread the virus when they have symptoms," says Johnson.

What the researchers found out was quite different. For those who had antibodies for genital herpes, but did not have a history of the disease, the virus turned out to be active about 10 percent of the time.

"Even people without a clinical history of genital HSV-2 are capable of spreading the virus to sexual partners," Johnson says.

Global implications

The finding has global public health implications. An infected woman can spread the virus to her baby during birth with devastating results. In an infant, the virus can cause blindness. It can infect the brain. It can also affect the baby's central nervous system causing seizures, meningitis and death.

There is no cure for genital herpes but medications can suppress it. The World Health Organization reports that 21 million people contract genital herpes each year. That's 21 million people whose disease also makes them three times more likely to contract AIDS from an infected partner.

"There have been many studies that HSV-2 is one of the main drivers of the HIV epidemic in places with high HSV-2 prevalence in such places as sub-Saharan Africa," says Wald.

She encourages physicians to advise patients to tell their sex partners if they have antibodies for herpes. Wald says most new infections come from people who have the antibodies but no symptoms of the herpes virus. She says doctors the world over need to encourage condom use and test sexually-active patients for this disease.