Estimates of the annual number and cost of new HIV infections among women attributable to trichomoniasis in the United States.

BACKGROUND: Clinical evidence suggests that trichomoniasis facilitates the sexual transmission and acquisition of HIV.

GOAL: The goal of this study was to estimate the annual number and cost of new HIV infections among women in the United States attributable to trichomoniasis.

STUDY: We used a mathematical model of HIV transmission to estimate the probability that a woman with trichomoniasis would acquire HIV as a result of her trichomoniasis-mediated increased susceptibility to HIV infection or as a result of increased HIV infectiousness in a trichomoniasis-infected male partner.

RESULTS: Our results indicate that each year in the United States, an estimated 746 new HIV cases among women can be attributed to the facilitative effects of trichomoniasis on HIV transmission. The lifetime cost of treating these trichomoniasis-attributable HIV infections is approximately $167 million.

CONCLUSIONS: Efforts to prevent trichomoniasis could help prevent HIV transmission and could reduce the economic burden associated with trichomoniasis-attributable HIV cases that occur each year. Because trichomoniasis is so common, however, a substantial number of cases would need to be detected and treated to have a discernible impact on HIV. Future research is needed to examine the cost-effectiveness of trichomoniasis prevention as a tool for HIV prevention.