There are two types of herpes simplex viruses: HSV-1, which infects 80 percent of the U.S. population and usually appears on the lips in cold sores; and HSV-2 is usually found in the genital area. However, if a person with HSV-1 oral herpes (cold sores) performs oral sex, it is possible for the partner to get HSV-1 genital herpes. And HSV-2 can infect the mouth through oral sex.
Genital herpes is spread only through direct skin-to-skin contact or mucous membrane contact. It can be transmitted through penile-vaginal intercourse, anal intercourse, oral-genital sex, and other sexual body-to-body contact. People who have the virus should avoid sexual contact from the time they first feel any symptoms until their lesions are completely healed.
Transmission Without Symptoms
In many instances, people with genital herpes know the virus is active because they have symptoms, such as lesions. But this isn't always the case.
The herpes virus can become active without causing symptoms. During these times, small amounts of the virus are present on the skin, often at the place of first infection. This reactivation without symptoms, known as "asymptomatic shedding," may also occur in rectal tissue or in fluids from the penis and vagina.
"Even if you're asymptomatic, you can transmit the virus," says Stanka Kukich, M.D., a medical team leader in the FDA's Center for Drug Evaluation and Research. In fact, studies have shown that most people get HSV from sexual contact during times of asymptomatic viral shedding.
Researchers have found that people with HSV-2 genital herpes tend to have more shedding than those with HSV-1. In addition, people with new infections are more likely to shed the virus than those with an infection more than a year old. Those with frequent recurrences may also shed the virus more often, but this is still an area being studied.
During Sexual Activity…
During times when there are no symptoms, using latex male condoms for genital-to-genital contact reduces the risk of transmission, according to the American Social Health Association. But condoms are only effective if they cover or prevent contact with the area of the body that has a lesion or active virus.
In one study of more than 400 monogamous couples in which one partner had genital herpes and the other didn't, condoms were found to offer significant protection against HSV-2 infection in women, says study leader Anna Wald, M.D., medical director of the virology research clinic at the University of Washington in Seattle.
Since women shed the virus from a wide genital area, condoms may be less protective for men than for women, says Wald, whose study was published in the June 27, 2001, issue of the Journal of the American Medical Association. However, more studies are needed to address how well condoms work for men, she says.
Lambskin or other natural membrane condoms should not be used for disease protection because the naturally occurring pores in the material are large enough to allow some viruses to pass through. The FDA recommends latex condoms or polyurethane condoms for those sensitive to latex.
Partners can be infected with different strains of herpes, but are highly unlikely to reinfect each other, says Ashley. Even if they did, each person's symptoms are unlikely to change. "You're not going to be suddenly having twice the attacks because you have [your partner's] strain too."
Other Modes of Transmission
The virus is not transmitted through the air, nor are there any documented cases of a person getting genital herpes from an inanimate object such as a toilet seat or hot tub. "Herpes doesn't do well in chlorinated water," says Rhoda Ashley, Ph.D., director of the University of Washington's diagnostic virology laboratory at the Children's Hospital and Regional Medical Center in Seattle. "The virus can be present in a hot tub, but it won't be active."
The virus doesn't survive well in the environment, even on a wet towel, says Ashley. However, she advises to avoid sharing razors, especially with someone who has an active cold sore. The virus can be transmitted from the razor to the skin. Other viruses, such as hepatitis C, also can be transmitted by sharing razors.
Spreading herpes from one part of your body to another (autoinoculation) is possible, but unusual. To be safe, wash your hands with soap if you touch a herpes sore. |
