Herpes simplex virus type 2 seropositivity and relationship status among U.S. adults age 20 to 49: a population-based analysis

BACKGROUND: U.S. population studies show herpes simplex virus type 2 (HSV-2) seroprevalence levelling by approximately age 30, suggesting few new infections after that age. It is unclear whether this pattern is driven by greater percentages in stable relationships, and to what extent adults who initiate new relationships may be at risk of incident HSV-2 infection. METHODS: Survey and laboratory data from the 1999-2008 waves of the U.S. National Health and Nutrition Examination Survey (NHANES) were combined for 12,862 adults age 20-49. Weighted population estimates of self-reported genital herpes, HSV-2 seroprevalence, and past-year sexual history were calculated, stratified by age, sex, race, and relationship status. Multivariable logistic regression was used to assess whether relationship status provided additional information in predicting HSV-2 over age, race and sex, and whether any such associations could be accounted for through differences in lifetime number of sex partners. RESULTS: Those who were unpartnered had higher HSV-2 prevalence than those who were married/cohabitating. Among unpartnered 45-49 year olds, seroprevalence was 55.3% in women and 25.7% in men. Those who were married/cohabitating were more likely to have had a past-year sex partner, and less likely to have had two or more partners. The effect of age in increasing the odds of HSV-2 was modified by race, with higher HSV-2 prevalence among Black Americans established by age 20-24 years, and the effect of race decreasing from age 30 to 49. Relationship status remained an independent predictor of HSV-2 when controlling for age, race, and sex among those age 30 to 49; married/cohabitating status was protective for HSV-2 in this group (OR = 0.69) CONCLUSIONS: Whereas sexually transmitted infections are often perceived as issues for young adults and specific high-risk groups, the chronic nature of HSV-2 results in accumulation of prevalence with age, especially among those not in married/cohabitating relationships. Increased odds of HSV-2 with age did not correspond with increases in self-reported genital herpes, which remained low. Adults who initiate new relationships should be aware of HSV-2 in order to better recognize its symptoms and prevent transmission.