title: HSV-2 incidence by sex over four age periods to age 38 in a birth cohort.
abstract: OBJECTIVE
  To examine herpes simplex virus type 2 (HSV-2) incidence over four periods to age 38 in a birth cohort, and to compare risks for men and women, taking into account sexual behaviour.
  
  
  METHODS
  At ages 21, 26, 32 and 38, participants in the Dunedin Multidisciplinary Health and Development Study were invited to provide serum for HSV-2 serology, and information on sexual behaviour. HSV-2 incidence rates were calculated for four age periods, and comparisons made by sex and period, taking into account number of sexual partners.
  
  
  RESULTS
  By age 38, 17.3% of men and 26.8% of women had ever been seropositive for HSV-2. Incidence peaked for women from age 21 to 26 (19.1 per 1000 person-years) and men from age 26 to 32 (14.1 per 1000 person-years); it fell markedly for both from age 32 to 38 (5.1 and 6.8 per 1000 person-years for men and women, respectively). Overall risk was significantly higher for women: adjusted incidence rate ratio 1.9 (95% CI 1.4 to 2.7); the sex difference was most marked from age 21 to 26 (3.4, 95% CI 1.9 to 6.3).
  
  
  CONCLUSIONS
  Our findings are consistent with a greater biological susceptibility to HSV-2 among women, and with the increasing risk to the early/mid-20s for women and late 20s/early 30s for men, being driven by an increasing pool of prevalent infection. The reduced risk in the mid-30s is consistent with declining infectivity of long-term prevalent infections.
authors: Department of Preventive and Social Medicine, University of Otago, , Dunedin, New Zealand.
authors: Nigel
authors: N
authors: Dickson
authors: Antoinette
authors: A
authors: Righarts
authors: Thea
authors: T
authors: van Roode
authors: Charlotte
authors: C
authors: Paul
authors: Janette
authors: J
authors: Taylor
authors: Anthony L
authors: AL
authors: Cunningham
mesh_terms: D000328:Adult; D017677:Age Distribution; D015331:Cohort Studies; D005260:Female; D006558:Herpes Genitalis / Q000453:epidemiology* / Q000517:prevention & control; D018258:Herpesvirus 2, Human / Q000302:isolation & purification*; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D008297:Male; D009520:New Zealand / Q000453:epidemiology; D012307:Risk Factors; D017678:Sex Distribution; D012725:Sexual Behavior / Q000706:statistics & numerical data; D012747:Sexual Partners; D013997:Time Factors