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Incidence, reinfection, and reproductive morbidity of bacterial sexually transmitted infections among Kenyan adolescent girls and young women receiving systematic testing and treatment: a 4.5-Year prospective cohort analysis

Year: 2026

Type: article

Abstract: Background Sexually transmitted infections (STIs) remain a major burden among adolescent girls and young women (AGYW) in sub-Saharan Africa. We investigated STI incidence, reinfection, and reproductive morbidity in Kenyan AGYW receiving regular testing and treatment. Methods We analysed data from the KEN SHE study, which enrolled sexually active, HIV-negative AGYW aged 15–20 years in Kenya. At enrolment and every six months, participants were tested for Neisseria gonorrhoeae (GC), Chlamydia trachomatis (CT) and syphilis. Testing used nucleic acid amplification for GC/CT and rapid plasma reagin with treponemal confirmation for syphilis. Symptomatic or laboratory-positive participants received treatment per national guidelines. Pelvic inflammatory disease (PID) was diagnosed and treated syndromically. Andersen-Gill recurrent events Cox models with time-varying covariates assessed factors associated with incidence and reinfection. Findings Between December 2018 and November 2019, 2275 participants were enrolled and followed for a median of 54 months (interquartile range [IQR] 52–57). Overall, 1355 (60%) tested positive for at least one of GC, CT, or syphilis (72.5% asymptomatic). Overall incidence of GC/CT was 22.37 per 100 person-years (95% CI: 21.42–23.34), CT (19.06 per 100 person-years; 95% CI: 18.19–19.96), and GC (5.35 per 100 person-years; 95% CI: 4.89–5.83). Among those with GC/CT, 43% experienced at least one reinfection (25.20 per 100 person-years; 95% CI: 23.21–27.30). Overall, 13.4% (304/2275) received PID treatment; incident PID was 3.34 per 100 person-years (95% CI 2.97–3.75). Participants with untreated STIs had a PID incidence of 12.83 per 100 person-years (95% CI 9.90–16.30). Interpretation GC and CT incidence, reinfection, and PID remained high despite systematic testing and treatment, indicating substantial residual disease burden. Partner management, vaccination and prophylaxis require prioritization and integration. Funding Bill & Melinda Gates Foundation; Francis and Dorothea Reed Endowed Chair in Infectious Diseases.

Source: The Lancet Regional Health - Africa

DOI: 10.1016/j.lanafr.2026.100137