How is Herpes Transmitted to Others?

How does transmission occur during symptomatic recurrences?

If a person has a herpes sore on the lips, for example, he or she can spread herpes to the lips of another person through kissing. Infection can also be spread from the lips to the genitals during oral sex. This is why so many cases of genital herpes are caused today by herpes type 1.

If one has a herpes sore on the genitals, coitus or other unprotected sexual activity gives the virus a chance to spread, resulting most often in genital-to-genital transmission.

How does transmission occur during subclinical shedding?

The same principles and same scenarios hold. Unrecognized or "Subclinical" shedding has been documented in or around the mouth as well as in various genital sites such as the vagina, penis, and anus. Thus, if HSV is active, oral, anal or vaginal intercourse can cause transmission -- even when one has no visible sores or other signs and symptoms. This is how most herpes is transmitted.

How can I reduce the risk of giving this to my partner?

Because it's hard to pinpoint herpes' active phases, preventing transmission is not a simple matter. But, there are a number of measures you can take to lower the risk of transmitting herpes:

Refrain from sexual contact when symptoms are present--including prodrome. Following outbreaks, it's best to wait for two days after the skin heals up, since subclinical viral shedding is more likely at this time.

Use condoms: Because of the risk of transmission from subclinical shedding, it is helpful to use condoms for penetrative sex in between outbreaks. Condoms restrict contact between the penis and the mucosal surfaces of the vagina, mouth or anus, where subclinical shedding is known to occur. Be advised: Condoms may not cover all sites of viral shedding, and they don't provide a 100% guarantee against herpes transmission. For example, herpes sores may be present on the scrotum or upper thigh, or virus may be shed into vaginal secretions that would reach places not covered. Even in heterosexual men or women, virus is shed in the area around the rectum (perirectal HSV). Thus, contact by touching or rubbing with this region of the penile skin or vulvar area may result in exposure to the virus. Even limited contact can result in exposure to high quantities of the virus. Reducing this exposure means putting on the condom during foreplay. Condoms are about 50% effective in reducing transmission between sexual partners. Condoms are the best all-around form of protection against HIV and other sexually transmitted infections (STIs).

Consider Medication: Some research shows that the use of daily antiviral therapy dramatically lessens the rate of asymptomatic viral shedding as well as reducing the frequency of outbreaks (choose "Treatment" from the main menu). One of the antiviral medications used for the treatment of genital herpes (valaciclovir) Valtrex�, has been shown to reduce transmission of HSV between sexual partners. This is a recent discovery and an important new advance for patients with genital herpes to know about. It is the first time an anti-herpes medication has been shown to reduce transmission to a sexual partner. The study was conducted among monogamous couples in which one had genital herpes (HSV-2) and one who did not. that If the partner with HSV-2 took the antiviral drug valaciclovir in a dose of 500mg once daily, the transmission of infection was reduced 50%. The study duration was 8 months. How long this effect on reducing transmission will occur is unknown. But, other studies indicate valaciclovir does not lose its potency over time for reducing viral shedding. The transmission rate between such couples averages about 5% per year. Most of these couples did not use condoms even though counseled to do so.

Consider Outercourse: Touching, cuddling, kissing, sensual massage and many other ways of giving sexual pleasure carry less risk than penetrative intercourse. Contact with a herpes lesion, however, is never risk-free.

Which combination of these precautions is right for you? It's best to talk these over and make decisions with your partner. In doing so, note that your partner's medical history may be an important consideration. If he or she has already acquired herpes, for example, it may be important to know the type and discuss which precautions you still want to take.

What are the odds of infecting a partner?

Unfortunately, no single precaution listed above can guarantee protection for a sexual partner. And because it's difficult to organize scientific studies of sexual behavior, there's no easy way to rate the effectiveness of each risk reduction strategy.

In general, your sexual partner's risk of acquiring herpes will vary according to a number of factors. For couples in whom one partner has genital herpes and the other does not, it appears the average rate of transmission is about 5 to 10% per year when the couples simply refrain from intercourse during outbreaks. But this average obscures two important factors: 1) The risk to uninfected women is roughly three times greater than the risk to men, and 2) the risk of acquiring herpes type 2 is higher in those who have not previously been infected with herpes type 1. Consistent condom use and the use of antivirals reduces the risk of transmission.