The herpes simplex virus, or herpes, is categorized into 2 types:  herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2). HSV-1 is mainly transmitted by oral-to-oral contact to cause oral herpes (which can include symptoms known as “cold sores”), but can also cause genital herpes. HSV-2 is a sexually transmitted infection that causes genital herpes. Both HSV-1 and HSV-2 infections are lifelong. An estimated 3.7 billion people under age 50 (67%) have HSV-1 infection globally. An estimated 417 million people aged 15-49 (11%) worldwide have HSV-2 infection. Most oral and genital herpes infections are asymptomatic. Symptoms of herpes include painful blisters or ulcers at the site of infection. Herpes infections are most contagious when symptoms are present but can still be transmitted to others in the absence of symptoms. Infection with HSV-2 increases the risk of acquiring and transmitting HIV infection. Introduction Infection with the herpes