Herpes simplex 1 is one of two variations of the herpes simplex virus. The other variation of the herpes simplex virus is herpes simplex 2. Herpes simplex 1 infection does not always produce physical symptoms, but when it does the symptoms are typically an outbreak of blisters in the area of the mouth. These herpes simplex oral blisters are typically referred to as cold sores, and to a lesser extent fever blisters. It is possible for cold sores to be spread to the genital area of another person. When cold sores are present, herpes simplex 1 is extremely contagious. Herpes simplex 1 infection is not a serious threat to health.