Performance and comparison of self-reported STI symptoms among high-risk populations - MSM, sex workers, persons living with HIV/AIDS - in El Salvador.

Resource-limited countries have limited laboratory capability and rely on syndromic management to diagnose sexually transmitted infections (STIs). We aimed to estimate the sensitivity, specificity and positive predictive value (PPV) of STI syndromic management when used as a screening method within a study setting. Men who have sex with men (MSM), female sex workers (FSWs) and people living with HIV/AIDS (PLWHA) participated in a behavioural surveillance study. Data were obtained on demographics, sexual behaviours, STI history and service utilisation. Biological specimens were tested for genital inflammatory infections (Neisseria gonorrhoeae [GC], Chlamydia trachomatis [CT], Mycoplasma genitalium [MG], Trichomonas vaginalis [TV]) and genital ulcerative infection (syphilis and Herpes simplex virus-2). There was a high prevalence of Herpes simplex virus-2 (MSM 48.1%, FSW 82.0% and PLWHA 84.4%). Most participants reported no ulcerative symptoms and the majority of men reported no inflammatory symptoms. Sensitivity and PPV were poor for inflammatory infections among PLWHA and MSM. Sensitivity in FSWs for inflammatory infections was 75%. For ulcerative infections, sensitivity was poor, but specificity and PPV were high. Reliance on self-reported symptoms may not be an effective screening strategy for these populations. STI prevention studies should focus on symptom recognition and consider routine screening and referral for high-risk populations.