Recurrence of sexually transmitted infections is commonly found in a subpopulation of Austrian users of HIV pre-exposure prophylaxis.

BACKGROUND

In recent years there has been an increase in the diagnoses of sexually transmitted infections (STI) among men who have sex with men (MSM) using human immunodeficiency virus (HIV) pre-exposure prophylaxis (PrEP); however, data on PrEP users in Austria are limited.

PATIENTS, MATERIAL AND

METHODS

In June 2020, we initiated a prospective observational cohort study at Vienna General Hospital including PrEP users from Vienna. Participants underwent STI testing quarterly and provided behavioral information using a questionnaire.

RESULTS

Between June 2020 and December 2023 a total of 360 individuals (99% MSM) were enrolled comprising 379 person-years of follow-up. We identified 276 STIs in 154 individuals, of which 23% (36/154) were symptomatic. The incidence rates per 100 person-years were 29.9 (95% confidence interval, CI 24.3-35.3 per 100 person-years) for gonorrhea, 22.7 (95% CI 17.9-27.5 per 100 person-years) for chlamydia and 9.8 (95% CI 6.6-12.9 per 100 person-years) for syphilis. Extragenital infections accounted for 95% (97/102) of gonorrhea and 81% (65/80) of chlamydia cases. A case of HIV infection was recorded in a 20-year-old male with inconsistent PrEP use. Participants with one or more reinfection (18%; 65/360) accounted for 68% (187/276) of all STIs. Sexualized drug use (Chemsex) was reported by 44% (157/360) of participants and was significantly associated with higher rates of gonorrhea (38% vs. 21%, p < 0.001) and syphilis (17% vs. 5%, p < 0.001) but not chlamydia (26% vs. 19%, p = 0.118).

CONCLUSION

Throughout the study, 43% of participants experienced a bacterial STI, which was mostly asymptomatic and at extragenital sites. Chemsex was commonly reported and identified as a predictor for STI reinfection, underlining the importance of harm reduction strategies in Austrian STI prevention.