Herpes simplex virus (HSV), also known as herpes, is a common contagious infection that causes painful blisters and ulcers usually around the mouth and genitals. It is spread primarily through skin-to-skin contact.
In the United States, 50 to 80 percent of adults have oral herpes caused by HSV-1. Genital herpes, caused by HSV-1 or HSV-2, affects about one in six Americans aged 14 to 49.




