In some people the HSV infection causes cold sores, which erupt following a trigger event such as a cold. There are two types of herpes simplex infection: herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2). HSV-1 can also cause genital herpes, although HSV-2 is the main cause of genital herpes. You may be infected with HSV-1 or HSV-2 but not show any symptoms. A first (primary) infection with the cold sore virus is often different to the recurring cold sores which many people have. The infection gradually subsides and goes within 1-3 weeks.