Herpes simplex virus
World Health Organization Fact Sheets
01 May 2020
Infection with herpes simplex virus, commonly known as herpes, can be due to either herpes simplex virus type 1 (HSV-1) or herpes simplex virus type 2 (HSV-2). HSV-1 is mainly transmitted by oral-to-oral contact to cause infection in or around the mouth (oral herpes). However, HSV-1 can also be transmitted through oral-genital contact to cause infection in or around the genital area ( genital herpes). HSV-2 is almost exclusively transmitted through genital-to-genital contact during sex, causing infection in the genital or anal area (genital herpes).
Both oral herpes infections and genital herpes infections are mostly asymptomatic or unrecognized but can cause symptoms of painful blisters or ulcers at the site of infection, ranging from mild to severe.