As with almost all sexually transmitted infections, women are more susceptible to acquiring genital HSV-2 than men. On an annual basis, without the use of antivirals or condoms, the transmission risk of HSV-2 from infected male to female is about 8–11%. This is believed to be due to the increased exposure of mucosal tissue to potential infection sites. Transmission risk from infected female to male is around 4–5% annually. Suppressive antiviral therapy reduces these risks by 50%. Antivirals also help prevent the development of symptomatic HSV in infection scenarios, meaning the infected partner will be seropositive but symptom-free by about 50%. Condom use also reduces the transmission risk significantly. Condom use is much more effective at preventing male-to-female transmission than vice versa. Previous HSV-1 infection may reduce the risk for acquisition of HSV-2 infection among women by a factor of three, although the one study that states this has a small sample size of 14 transmissions out of 214 couples.
Both HSV-1 and HSV-2 infections are acquired from direct contact with someone who carries the virus. The infectious secretions that pass on HSV-1 or HSV-2 live on oral, genital or anal mucosal surfaces. They’re passed through skin-to-skin transmission, and any form of direct contact with sores on the mouth, buttocks or genitals can cause the virus to be passed.
“You don’t want an infant delivered through infected birth canal or vulva because the infant can be infected,” Cullins explains. A neonatal herpes infection is a real risk because it can cause problems with brain development and eye and skin infections, or even be fatal. And since there is more risk for transmission from mother to baby during an initial outbreak than during a recurrent outbreak, the CDC stresses that it’s incredibly important for pregnant women to avoid contracting a new herpes infection.
However, asymptomatic carriers of the HSV-2 virus are still contagious. In many infections, the first symptom people will have of their own infections is the horizontal transmission to a sexual partner or the vertical transmission of neonatal herpes to a newborn at term. Since most asymptomatic individuals are unaware of their infection, they are considered at high risk for spreading HSV.
These herpes viruses enter the body through small cuts, abrasions, or breaks in the skin or mucous membranes. The incubation period for herpes simplex infections is about three to six days. Transmission (spread) of the virus is person to person and more likely to occur if blisters or lesions are present. The majority enter after an uninfected person has direct contact with someone carrying the virus (either with or without noticeable lesions). Simply touching an infected person is often the way children get exposed. Adolescents and adults frequently get exposed by skin contact but may get their first exposure by kissing or sexual contact (oral and/or genital contact), especially for HSV-2. Statistical studies suggest that about 80%-90% of people in the U.S. have been exposed to HSV-1 and about 30% have been exposed to HSV-2. Usually, the contagious period continues until lesions heal. Some people (estimated from 30%-50%) occasionally shed herpes virus while having few or no associated symptoms or signs.
Doctors prescribe suppressive treatment if a person experiences more than six recurrences in a year. In some cases, a doctor my recommend that the individual takes daily antiviral treatment indefinitely. The aim here is to prevent further recurrences. Although suppressive treatment significantly reduces the risk of passing HSV to a partner, there is still a risk.
If you have herpes, you should talk to your sex partner(s) and let him or her know that you do and the risk involved. Using condoms may help lower this risk but it will not get rid of the risk completely. Having sores or other symptoms of herpes can increase your risk of spreading the disease. Even if you do not have any symptoms, you can still infect your sex partners.
The herpes virus can be shed from an infected person even when there are no lesions visible. So caution is important. Some may wish to take the daily prophylactic oral drug Valtrex (an antiviral oral medication) to help cut down on shedding. Herpes can also be transmitted on any skin: fingers, lips, etc. Depending on sexual practices, herpes simplex can be transferred to genitals and or buttocks from the lips of someone who has fever blisters. Honesty between partners is very important so these issues can be discussed openly.
A scary finding is that more cases of genital herpes than ever before are now being caused by HSV-1 (the type most people assume only causes mouth sores), and about 85 percent of people with genital herpes don’t even know it. (7) Studies show that about 50 percent of the new genital herpes infections in young adults are due to HSV-1 and about 40 percent in older adults. The fact that most people don’t ever find out they’re infected is one of the reasons that transmission rates are steadily climbing.