Herpes is most easily spread when a sore is present, but, it is also often spread at other times too. Some people notice itching, tingling or other sensations before they see anything on their skin. These are called “Prodromal Symptoms” and they warn that the virus may be present on the skin.
Herpes is most likely to be spread from the time these first symptoms are noticed until the area is completely healed and the skin looks normal again. Contact with the infected area (including kissing, oral, vaginal, or anal sex) is very risky during this time.
If there are no symptoms occurring in the infected area at the time of contact there is still a small chance of spreading the virus because occasionally the virus can shed itself at the skin’s surface (in the area of infection).
Although it is impossible to predict when viral shedding is occurring it is estimated that it only occurs approximately 5% of days during the year (possibly even less after having the virus for a long period of time) and this is usually during the few days just before and after an outbreak.