Background Sexually-transmitted infections (STIs) in adolescents and young women (AGYW) increase the risk of infertility and the risk of HIV acquisition. Recent data on STIs in African AGYW are limited because of syndromic management and lack of STI testing. PrEP programs that test for STIs can provide critical epidemiologic data to guide policies.

Methods Sexually-active HIV-uninfected AGYW (16–25 years) in a township near Cape Town, South Africa were enrolled in the 3Ps for Prevention Study to evaluate PrEP uptake and adherence. Nucleic acid amplification testing for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) and a rapid test for Trichomonas vaginalis (TV) was conducted at screening and 6 months, and infections were treated. Symptom screening was performed at each visit. Predictors of incident STIs were analysed via Poisson regression to evaluate potential targeting of STI screening.

Results 200 AGYW were enrolled with a median age of 19 (IQR 17–21). At screening one-third of women tested positive for a curable STI: 25% CT, 11% NG, and 6% TV, 98% of whom were asymptomatic. At month 6, the incidence of a curable STI was 52/100 person-years (100py); CT 42/100py, NG 14/100py and TV 10/100py. Most incident STIs were diagnosed in women who did not have these infections at enrolment: 62% of 39 incident CT, 77% of 13 incident NG, and 89% of 9 incident TV infections. No significant associations were found between age, hormonal contraception or IPV and incident STIs.

Conclusion South African AGYW in a PrEP demonstration project had very high prevalence and incidence of asymptomatic curable STIs. Offering STI testing and treatment in PrEP programs is an important reproductive health service, and is valued by AGYW. Treatment of partners and innovative strategies to prevent STIs, including doxycycline post-exposure prophylaxis and vaccines, need to be evaluated in African AGYW.

Disclosure No significant relationships.