Background

Genital herpes is an extremely common infection caused by one of the two related Herpes simplex viruses, HSV-1 and HSV-2. HSV-1 is the cause of cold sores around the mouth but can infect the genitals and be transmitted either oro–genitally or by genital–genital contact. HSV-2 is mainly a genital infection although orolabial infection can occur. Both viruses establish lifelong infections in the nerve roots and can be periodically reactivated causing recurrent episodes. During episodes small blisters appear which are itchy or painful and which break down in about a day to leave an open sore, which usually heals in about a week in those who are immunocompetent. However inapparent lesions are common and asymptomatic shedding, production of virus in the absence of lesions, also occurs in the absence of frank episodes. Most infections are believed to result from inapparent lesions or asymptomatic shedding since avoidance of sex during obvious episodes is common.

Genital recurrence rates are higher on average for HSV-2 than for HSV-1. Some individuals have only a single obvious episode, others can have episode rates up to one per fortnight. While episodes usually diminish in frequency over the years there is considerable variation. Infection is lifelong and cannot be eliminated. Treatment is by antivirals which, when used on a continuing basis, largely or completely suppress episodes during active treatment but do not affect natural history.

Most people with genital herpes have never been diagnosed and are unaware that they are infected.