Increasing proportion of herpes simplex virus type 1 as a cause of genital herpes infection in college students.
A retrospective review of genital herpes simplex virus (HSV) isolates collected in a university student health service over a 9-year period showed that an increasing proportion of isolates were HSV-1 rather than HSV-2. HSV-1 accounted for 78% of all genital isolates in this population by 2001, compared with 31% of isolates in 1993.


BACKGROUND
Herpes simplex virus (HSV) type 1 is usually thought to cause less than 30% of genital herpes infections in the United States, but the proportion of infections resulting from HSV-1 is increasing in some populations.


OBJECTIVE
The goal was to review the relative proportion of HSV-1 and HSV-2 as the cause of newly diagnosed genital herpes infections in a population of U.S. college students and to assess trends in the change of this proportion over time.


METHODS
Genital HSV isolates collected at a university student health service from 1993 to 2001 (n = 499) were reviewed retrospectively. Analyses included comparisons of isolates by HSV type, age group, and sex.


RESULTS
The proportion of newly diagnosed genital herpes infections resulting from HSV-1 increased from 31% in 1993 to 78% in 2001 (P <0.001, linear trend P <0.001). HSV-1 was more common in females than males, but increases were noted for both sexes. HSV-1 was more common in persons aged 16 to 21 than in persons aged 22 or older.


CONCLUSIONS
HSV-1 has become the most common cause of newly diagnosed genital herpes infections in this population of college students and reflects a reversal of the usual HSV-1/HSV-2 ratio.
Roberts
Craig M
CM
University Health Services, University of Wisconsin-Madison, Madison, Wisconsin 53726, USA. cmrober1@wisc.edu
Pfister
John R
JR
Spear
Scott J
SJ
D000293:Adolescent; D000328:Adult; D005260:Female; D006558:Herpes Genitalis / Q000453:epidemiology* / Q000821:virology*; D018259:Herpesvirus 1, Human / Q000302:isolation & purification*; D018258:Herpesvirus 2, Human / Q000302:isolation & purification*; D006801:Humans; D008297:Male; D015146:Midwestern United States / Q000453:epidemiology; D013334:Students / Q000706:statistics & numerical data; D014495:Universities