Genital herpes infection increasingly caused by HSV-1

(14 Feb 2003)

Although the herpes simplex type 2 virus (HSV-2) is regarded as the primary cause of genital herpes, a new study suggests more and more cases are occurring as a result of HSV type 1(1). HSV-1 is generally responsible for facial herpes which most commonly causes cold sores around the mouth.

A Specialist Virology Centre based in the West of Scotland was responsible for processing 99 per cent of all HSV samples taken in the region between January 1986 and December 2000. Researchers at the centre examined 3,126 samples taken from people with genital herpes infection. Between 1986 and 1988 they found 33% of genital HSV infection was due to HSV-1, but by 2000 this had risen to over half (56%).

HSV-1 was most often seen in women - particularly those under 25 years of age. These findings are consistent with genital HSV-1 trends noted in other studies.

Genital HSV-1 infection tends to be milder and less frequent than infection with HSV-2, but anyone who is sexually active should be aware of the risk of practising unprotected oral sex with a partner who has facial herpes. It is also possible to shed infectious virus particles without noticeable symptoms, many people are infected with facial herpes without knowing it so even in the absence of cold sores transmission might still occur.

For more information please refer to the IHA leaflet on "Facial Herpes" under the 'Resource' Section of the website.

Ref:

(1) Scoular A et al. Longitudinal study of genital infection by herpes simplex virus type 1 in Western Scotland over 15 years. BMJ 2002; 324:1366-1367