Shedding light on viral shedding

Dear The asymptomatic,

Herpes is one of the most prevalent sexually transmitted infections. The herpes virus makes its home in the nerve cells of an infected person and at times, the virus travels along the nerves up to the surface of the skin. This process is called "viral shedding.” During shedding, the virus can be passed on to others by direct skin-to-skin contact — especially from anal, oral, or vaginal sex. Occasionally, shedding is accompanied by other symptoms such as blisters. However, sometimes shedding occurs without any noticeable symptoms — this is referred to as "asymptomatic shedding."

When a person is experiencing asymptomatic shedding, it's virtually impossible to know when s/he is contagious because there aren't any obvious symptoms or sensations. Because people are more likely to engage in sexual activity when they are not experiencing symptoms, it is more common for herpes transmission to occur during such periods. However, using condoms between outbreaks can reduce the risk of transmission. A person is most contagious when herpes blisters are present — as shedding is definitely taking place and precautions need to be taken to prevent spreading the virus such as temporarily avoiding intimate or sexual contact with others.

It’s hard to recognize how often asymptomatic shedding occurs in an infected individual since it is invisible to the naked eye. Trying to recognize or track contagious periods is difficult, but medications are available that greatly reduce shedding and therefore substantially lower the risk of herpes transmission. Individuals who are considering taking medicine to decrease (but not eliminate) the risk of passing herpes on to others should discuss this option with their health care provider. 

Researchers have found that in nearly all infected people, asymptomatic shedding was present on 20 percent of days, although frequency and duration can be reduced using drug therapies. Another study found that shedding was present on 20 percent of days with a an average duration of 13 hours — but 20 percent of shedding incidences lasted less than 6 hours. Studies have also found that 50 percent of asymptomatic shedding occurs in the 7 days before and after an outbreak with noticeable symptoms. Because the frequency of these obvious outbreaks is highly variable, it is likely that the frequency of asymptomatic shedding also varies from person to person. But regardless of how often it happens, all people carrying the herpes virus experience periods of shedding at one time or another.

To learn more about herpes, check out the Go Ask Alice! herpes archives. If you’re a Columbia student on the Morningside campus, check out the sexual health map for information on where to get condoms (both male and female) and other safer sex supplies. You can also make an appointment with your medical provider at Medical Services using the Open Communicator or by calling 212-854-7426. If you’re on the Medical Center campus, the Center for Student Wellness carries a variety of safer sex supplies including male and female condoms and both water-and silicone-based lubricant. Students at the Medical Center can make an appointment with Student Health by calling 212-305-3400.