Herpes simplex type I (one), or HSV-1 (H-S-V one), is a virus that most often affects the mouth, lips, and face, causing tiny, fluid-filled blisters. These lesions are called 'cold sores' or 'fever blisters', and in fact, later outbreaks may be triggered by fever or viral infection. HSV-1 is usually acquired during childhood from family members or friends. A person can become infected by kissing; sharing cups, towels, lip balms, or eating utensils; or by contact with respiratory secretions like coughs or sneezes. Dentists, nurses, and doctors can also get herpes type I infections on their fingers through contact with infected patients. Though HSV-1 isn't considered a sexually transmitted disease, it can be spread to the genitals through oral sex. By age 20, most people are thought to harbor the virus, but only certain individuals will have outbreaks of blisters. The virus remains in the body indefinitely. In those who have recurrent attacks, symptoms are usually milder than during the initial outbreak. Prior to the formation of blisters, a person may feel itching, tingling, or sensitivity in the area. While HSV-1 is most contagious when active, oozing blisters are present, it may also be shed in saliva when no blisters are observed.