Background:
Among sexually active women aged 20-49 years in the U.S., 27% are infected with herpes simplex virus type 2 (HSV-2) and 30% have bacterial vaginosis (BV). In prospective studies, BV has been found to increase the risk of HSV 2 acquisition.

Objective:
To describe the prevalence of HSV-2 in relation to BV status among sexually active women in the U.S.

Method:
We analyzed data from sexually active women aged 20-49 years who participated in the National Health and Nutrition Examination Surveys (NHANES), a series of complex, multi-stage, probability surveys conducted in a national representative sample of the civilian, non-institutionalized population of the U.S., from 2001-2004. BV status was determined using Nugent criteria (score of 7-10=positive); HSV-2 was determined using an immunodot assay.

Result:
The prevalence of HSV-2 among women without BV was 22.6% (95% confidence interval [CI] 20.3%-25.0%) and with BV was 37.2% (95% CI 33.6%-41.2%). HSV-2 prevalence ratios by BV status for women aged 20-29, 30-39, and 40-49 years were all >1.5 (p<0.01). Compared to women without BV, HSV-2 prevalence was higher among those with BV: Among women with 1-4 sex partners with BV, HSV-2 prevalence was 20.1%, and without BV was 13.1% (p=0.06); among women with 5-9 lifetime sex partners 40.5% vs 24.9 (p=0.003); among women with 10 or more partners 58.4% vs 39.1% (p<0.001); among non-Hispanic white women 29.1% vs 18.7% (p=0.008); and among non-Hispanic black women, 65.6% vs 52.9% (p=0.006).

Conclusion:
BV positivity was associated with higher HSV-2 prevalence among all age groups, among women with different numbers of lifetime sex partners, and among non-Hispanic whites and non-Hispanic blacks.

Implications:
BV may be a risk marker for other sexually transmitted infections; further research should clarify how BV increases this risk.