136 Asymptomatic Sexually Transmitted Infections Are Commonly Detected in Austrian PrEP-Users

Pre-exposure prophylaxis (PrEP) is a well-established method for HIV prevention. Current guidelines suggest frequent screening & sexually transmitted infections (STI) of risk-populations – in high-income countries primarily men who have sex with (MSM) and subsequent PrEP-initiation. Since little known about Austrian PrEP-users, we initiated an observational cohort study to investigate behavioral characteristics HIV/STI-prevalence this population. All HIV-negative individuals at the Department Dermatology General Hospital Vienna starting or using PrEP between 07/2020-12/2021 were considered inclusion. Details on sexual behavior addressed by questionnaire. Overall, 131 prospectively enrolled could choose daily- (73%, 96/131) on-demand (27%, 35/131) PrEP-services. 99% (130/131) MSM (median age 33.8 years) 60% (79/131) reported previous STIs. The median number partners was 10 (range 1-200), engagement active/passive condomless anal intercourse 70% (84/120) ‘chemsex’ 67% (85/126) within past twelve months. No patient tested positive viral hepatitis. Syphilis affected 8% (10/131) while mucosal (pharyngeal, anal, urethral) sampling revealed pooled prevalence 16% (21/131), 10% (13/131) 17% (22/128) gonorrhea, chlamydia mycoplasma genitalium, respectively. Forty percent (52/131) patients had least one STI, however, only (5/52) symptomatic. Multivariate analysis identified preference daily PrEP-use (adjusted-OR 3.26 95%-CI (1.28-8.26)) as independent predictor presence STI. PrEP-users engage high-risk practices HIV-transmission are frequently asymptomatic Improved implementation public PrEP-services necessary reducing burden STIs Austria.