T. vaginalis and C. trachomatis: Whom should we screen?

Infections with T. vaginalis (Tv) and C. trachomatis (Ct) are common among young adults. Since the majority of infections are asymptomatic, screening is an effective strategy for prevention of long-term health effects. However, current guidelines recommend Ct screening only for women <25 years and there is no active surveillance of Tv in the U.S.

The Monitoring STIs study tracks the prevalence, over a 3-year period, of these sexually transmitted infections among a probability sample of young adults aged 15-35 years in Baltimore, Maryland – an urban area with historically high rates of STIs. The study combines telephone surveys with STI testing of mail-in urine specimens. Data collection for the first year of the project was completed September 2007.

Preliminary findings from nearly 750 adults in year one suggest that Tv infections are common (6.3% overall), particularly among women (10.2%; OR=5.6, 95%CI 2.0, 15.3), and among those reporting a previous Tv diagnosis (OR=5.3, 95%CI 2.4, 11.6). Conversely, we detected more Ct infections among men (6.2%) than women (3.5%; OR=1.8, 95%CI 0.7, 4.3); however rates were significantly higher among those with previous Ct (OR=3.9, 95%CI 1.4, 9.9) and respondents aged 20 years or younger (OR=3, 95%CI 1.2, 7.6). Rates of both infections were higher among Blacks than other racial/ethnic groups.

These results suggest that within high-risk populations, public health interventions aimed at reducing STIs should consider Tv screening and expansion of Ct screening for men and persons with a history of previous infection.