What is the difference between HSV-1 and HSV-2?
A. Herpes simplex virus HSV type 2 (HSV-2) is the usual cause of genital herpes and is always acquired by genital (or anal) contact with another person. HSV type 1 (HSV-1) is the cause of herpes sores on the lips and in the mouth (often called fever blisters or cold sores). It also causes up to 50% of initial genital herpes infections, usually acquired during oral sex. Genital HSV-2 infection almost always recurs frequently, with or without symptoms, whereas HSV-1 genital herpes reactivates infrequently. Therefore, the large majority of recurrent genital herpes is due to HSV-2.
