Trichomonas vaginalis Prevalence in the United States, 2013-2016

Trichomonas vaginalis
Trichomonas vaginalis
Among noninstitutionalized adolescents and adults in the United States between 2013 and 2016, 1.3% tested positive for Trichomonas vaginalis infection.

Among noninstitutionalized adolescents and adults in the United States between 2013 and 2016, 1.3% tested positive for Trichomonas vaginalis infection, according to a study published in Sexually Transmitted Diseases. The study also determined that T vaginalis was more prevalent in women than men, specifically among non-Hispanic black women.

Trichomoniasis is a sexually transmitted parasitic infection caused by T vaginalis and is treatable and curable, but is associated with preterm delivery. Using nucleic acid amplification test results from National Health and Nutrition Examination Survey (NHANES) urine specimens obtained between 2013 and 2016, investigators assessed the prevalence of T vaginalis in adolescents and adults between the age of 14 years and 59 years by health, demographic, and sexual behavior factors. The stability of these estimates was examined, as was nonresponse, in order to account for biases in the data.

Among the NHANES interviews, the response rate among adult participants between the age of 20 and 59 years was 61.9%, with 58.4% T vaginalis test completion, and 52.3% participation in the sexual behavior questionnaire. However, among the study cohort in general, T vaginalis prevalence was 1.3% (95% CI, 1.0%-1.7%). Prevalence was significantly lower in men compared with women (0.5%; 95% CI, 0.3%-0.7% vs 2.1%; 95% CI, 1.6%-2.8%), and very low in women aged 14 to 19 (0.7%; 95% CI, 0.4%-1.5%).

Prevalence in adult women between the age of 20 and 29 years was 2.7% (95% CI, 1.8%-4.0%) and did not differ significantly for women aged 30 to 39 years or 40 to 49 years, but was lower in women between the age of 50 and 59 year (1.4%; 95% CI, 0.8%-2.5%). T vaginalis prevalence was significantly higher in non-Hispanic black women (9.6%; 95% CI, 7.3%-12.5%) compared with non-Hispanic white women (0.8%; 95% CI, 0.4%-1.5%), but not in Hispanic women (1.4%; 95% CI, 0.8%-2.2%). Prevalence in non-Hispanic black men was 3.4% (95% CI, 2.3%-4.9%), but estimates for all other race/ethnicity groups among men were unstable.

Estimates showed that poverty, lower level of education attainment, being unmarried, and having been born in the United States were all significantly associated with T vaginalis infection, as were younger age at sexual debut, more lifetime and/or prior 12-month sexual partners, and prior 12-month chlamydia infection. Most of these estimates, however, were unstable in men and were not shown in the study.   

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Study investigators noted that this study “is the first report to include data from adolescent males and females,” adding that “low infection prevalence among most subpopulation groups constrains detailed exploration of factors associated with this infection using NHANES data. Other data sources are needed to understand the disproportionate burden of T vaginalis infection, particularly among non-Hispanic blacks.”


Flagg EW, Meites E, Phillips C, Papp J, Torrone EA. Prevalence of Trichomonas vaginalis among males and females aged 14-59 years: United States, 2013-2016 [published online May 27, 2019]. Sex Transm Dis. doi: 10.1097/OLQ.0000000000001013