Trends in Herpes Simplex Virus Type 1 and 2 Infections Among Patients Diagnosed With Genital Herpes in a Finnish Sexually Transmitted Disease Clinic, 1994–2002

OBJECTIVE: The objective of this study was to analyze the proportion of herpes simplex virus types 1 and 2 (HSV-1 and -2) in genital infections during a 9-year period (1994-2002) in a Finnish sexually transmitted disease (STD) clinic population. STUDY DESIGN: We analyzed prospectively the proportion of HSV-1- or -2-positive culture samples from our STD clinic patients with genital herpes during years 1994-2002 and compared the proportions of HSV-1 and HSV-2 findings with the age and gender of the patients. RESULTS: The proportion of HSV-1 infections increased from 18.7% (39 of 209) in 1994-1996 to 25.9% (52 of 201) in 2000-2002 (P = 0.032). Female patients with genital herpes and laboratory isolation of HSV-1 were 35.9% of the cohort from 1994-1996 and 67.3% of the cohort from 2000-2002. The mean age of male patients with HSV-1 decreased from 29.3 years in 1994-1996 to 24.1 years in 2000-2002 (P = 0.023). CONCLUSIONS: An increase in the proportion of genital infections caused by HSV-1 was found. The increase was mainly the result of the increase in the number of female patients with HSV-1. Male patients acquire genital HSV-1 infection at a younger age than 10 years ago.