Most people get HSV-1 infections during infancy or childhood and usually catch the virus from an infected family member or friend. Only an estimated 30 percent of those infected actually develop the characteristic blisters. If sores do develop, they can appear anywhere from two to 12 days after exposure to an infected person. Other persons with a primary infection may have flu-like symptoms such as a high fever, sore throat, swollen neck glands and mouth soreness.

Reviewed: January 2012