(PL25) MOLECULAR TESTING FOR TRICHOMONAS VAGINALIS IN 34306 SAMPLES FROM WOMEN WITH VAGINAL DISCHARGE AND ASYMPTOMATIC WOMEN OF ALL ETHNICITIES THROUGH AN ONLINE POSTAL SELF SAMPLNG SERVICE FOR STIS

Background:
An online postal self-sampling service (OPSS) with symptomatic triage enabled females reporting vaginal discharge to be tested for Trichomonas vaginalis (TV). Asymptomatic testing in selected regions allowed us to estimate local TV prevalence.

Methods:
Using the highly sensitive and specific cobas TV assay (Roche), we tested women for TV through online STI testing services in 23 areas of England.  We analysed 34,306 samples from:

Females from all ethnicities reporting vaginal discharge (n=24,812)

Asymptomatic females: White British (n=2016), all other ethnic groups (n=7478)

TV positivity rates were compared by ethnicity, age, deprivation decile, sexuality, and urban/rural classification.

Results:
Overall TV positivity across all cohorts was 3.7% (1261/34306), with 4.4% (1099/24812) positivity in females with vaginal discharge, 1.2% (24/2016) in asymptomatic White British females and 1.8% (13/7478) in asymptomatic females from all other ethnic groups combined.

In symptomatic women, positivity was highest in those of Black Caribbean/White and Black Caribbean (9.0%), Black African (5.1%), and White and Black African (6.5%) ethnicities. White British women reporting discharge had 4.0% TV positivity. There was a linear association between deprivation and higher TV positivity, with 7.6% recorded in the most deprived area and a 1.5% in the least deprived areas.

Comparing TV positivity and Neisseria gonorrhoeae (NG) positivity in these cohorts (tested with NG NAAT on the same 34,306 samples), TV positivity was higher across all groups:

Symptomatic - 4.4% (1099) vs. 1.4% (354)

Asymptomatic Ethnic Minority Women - 1.8% (138) vs. 0.8% (56)

Asymptomatic White British - 1.2% (24) vs. 0.5% (11)

for TV and NG, respectively.

Conclusion:
The high TV positivity rate among women with vaginal discharge seen in this study supports the use of an online triage to identify symptoms and provide the most clinically appropriate tests.

Further evidence is needed to help determine the most appropriate use of TV testing among asymptomatic populations.