Researchers reviewed all genital samples of herpes simplex processed between 1986 and 2000 at the West of Scotland Specialist Virology Centre.
Of the 3,181 swabs testing positive for the virus, 63% were from women and 37% were from men. Twenty-nine per cent of patients were aged 21-25 years. In 1986-1988, 33% of all positive swabs were due to HSV-1, rising progressively to 56% in 1998-2000.
Both the number and percentage of HSV-1 infections have risen, say the authors. Genital infection with HSV-1 is also strongly associated with being young (aged less than 25 years) and being female.
Most new cases of genital HSV-1 infection are likely to be due to orogenital transmission, but there is no evidence suggesting that oral sex practices have changed substantially, say the authors. The occurrence of HSV-1 infection in women is unexplained.
These results suggest that counselling and clinical management strategies may need to be revised, say the authors. Preventive strategies for genital herpes should focus on the risk of unprotected orogenital intercourse, which is frequently perceived as "safe" in the context of sexually transmitted infections, they conclude.