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More Genital Herpes From Cold Sore Virus

More Genital Herpes From Cold Sore Virus

WebMD Health News

Oct. 3, 2002 - The virus that triggers "cold sores" of the mouth is becoming an increasingly common cause of genital herpes -- and the source of that upswing may be people who begin having sex while in or before high school.

In the past, nearly all cases of genital herpes, which affects about one in five Americans, most of them unaware of their condition, resulted from unprotected sexual intercourse with someone infected with the herpes simplex virus-2. Herpes simplex virus-1 (HSV-1) has traditionally caused cold sores (or fever blisters).

"But now, we're seeing more cases of genital herpes that result from HSV-1," Rhoda Ashley-Morrow, PhD, researcher at the University of Washington, tells WebMD. "In the U.K., as many as 60% of new genital herpes infections are due to HSV-1. Here in Seattle, about one-third of new cases are caused by HSV-1."

And sexually active kids may be largely responsible, according to a new study.

Morrow's study shows that people who began having sex by age 15 were up to 60% more likely to be infected with HSV-1 than those who first had sex at age 20 or older. Published in the October issue of the medical journal Sexually Transmitted Infections, the study suggests those who begin having sex at an earlier age "are particularly vulnerable to infection with HSV-1" and may spread genital herpes without having intercourse.

"The younger you are, the less immunity you have to HSV-1," she tells WebMD. "And the assumption is being made that there is more oral-genital contact among young people with HSV-1." However, the researchers cannot be certain if kissing, oral sex, or intercourse transmitted the infections. Kissing or even touching the lips of someone with an active cold sore caused by HSV-1 can lead to genital herpes if you then touch your own genitalia.

Half of all American high school students are sexually active, according to federal statistics. This includes more than 60% of boys and girls in 12th grade, and 33% of girls and 45% of boys in 9th grade. Of those, only about half of the seniors and two-thirds of 9th graders use condoms, which can prevent the spread of genital herpes and other sexually transmitted diseases, according to the CDC.

Once infected with either form of herpes, the virus typically lies dormant in nerves and occasionally breaks out into highly contagious sores that cause burning, itching, redness, and ulcers in the infected area.

Of the one in five Americans infected with genital herpes, experts believe that up to 90% of those may be unaware of their condition. Although outbreaks and symptoms can be controlled with prescription drugs, there is no cure. And genital herpes increases susceptibility to HIV by making it easier for the AIDS virus to get into the body.

While the rate of genital herpes has increased in the U.S. at least 33% since the 1970s, the prevalence of HSV-1 has steadily declined in recent decades because of improved hygiene and better socioeconomic conditions. Some 60 years ago, infection with HSV-1 was almost universal; now about half of adults are infected, says Morrow.

Although known as "cold sores" or "fever blisters," the sores of HSV-1 aren't caused by colds or fever, rather, the virus can activate during times when immunity is suppressed or when the body is stressed. "There are a lot of theories, but the only thing that we know causes an HSV-1 outbreak is close exposure to ultraviolet light," says Morrow. "That is why it's recommended to wear sunscreen on your lips and other susceptible areas."

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