Systematic three-site vs. classical single-site screening for Chlamydia trachomatis and Neisseria gonorrhoeae infections in non-sex worker women: the multicentric Sexually Infections Still Transmitted by Remote Sites (SIST’RS) study

OBJECTIVES: Guidelines recommend extragenital screening for sexually transmitted infections in men having sex with men but not for women who do not report extravaginal intercourses. However, it has been suggested that among female commercial sex workers, limiting sexually transmitted infection screening to vaginal samples would miss a sizeable number of infections. No study exists for nonsex worker women. Therefore, our objective was to assess the potential benefit of systematically testing three anatomical sites (oral, anal, and vaginal) versus only vaginal testing in women attending free sexually transmitted infection screening centres in France. METHODS: A prospective longitudinal study was conducted in seven hospitals in France between April 2023 and September 2024 in which women were offered to be tested at the three sites instead of vaginal only. RESULTS: A total of 1498 women were included in the study, and 1483, 1492, and 1278 oral, vaginal, and anal samples, respectively, were reported. With a three-site strategy, the detection rate increased from 151/1492 (10.1%) to 179/1295 (13.8%) (p < 0.001) (127 [10.0%] to 152/1268 [12.0%]; p < 0.001 for all patients with three-site samples) for both infections (p < 0.001). Similarly, rate increased from 137/1492 (9.2%) to 160/1293 (12.4%) (p < 0.001) (114 [9.0%] to 135/1268 [10.7%]; p < 0.001 for all patients with three-site samples) for Chlamydia trachomatis and from 21/1492 (1.4%) to 30/1270 (2.4%) (p 0.008) (20 [1.6%] to 28/1268 [2.2%]; p 0.01 for all patients with three-site samples) for Neisseria gonorrhoeae. Neither symptoms nor reported sex practices were reliable predictors of infection. Among the C. trachomatis or N. gonorrhoeae infections detected, 15 (10.0%) and 25 (17.0%) were exclusively anal or anal-oral infections, respectively, without vaginal involvement. CONCLUSIONS: Multisite testing should be considered for women to ensure accurate diagnosis and treatment of C. trachomatis and N. gonorrhoeae.