Geospatial mobility, non-local partners, concurrent sexual partnerships, and gender influence longitudinal STI prevalence in rural eastern Africa.

BackgroundMobility challenges HIV prevention efforts through associated risk behaviours and sexually transmitted infections (STIs). We characterized relationships between mobility and sexual risks on STI prevalence over time in East Africa.MethodsGeospatial mobility and sexual risk behaviours were collected in 12 communities using a sex- and HIV-stratified random sub-sample of 2750 adults from a longitudinal cohort (2015-2019) of a HIV test-and-treat trial in Kenya and Uganda. Annual Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) testing was performed and relationships of prevalent STIs with mobility, sexual concurrency, and higher HIV-risk sexual partners (defined as one night stand, stranger, commercial sex worker/client, casual partner, or inherited partner/inheritor) were examined.ResultsThe annual prevalence of CT or NG among 2665 participants tested was 3.1% (95% CI: 2.5-3.9) at baseline, 3.3% (95% CI: 2.6-4.0) at year 1, 4.4% (95% CI: 3.0-5.2) at year 2, and 4.8% (95% CI: 4.0-5.7) at year 3. STI (CT, NG) prevalence was associated with migration in the past year, sexual partnership concurrency, being single, higher HIV-risk partners, age >25, low household wealth, and the relationship between gender and work-related travel in past 6 months. The association between select STI prevalence and past 6-months travel was mediated by higher HIV-risk sexual partners, partnership concurrency, out-of-town partner, and higher HIV-risk transactional sex partners.ConclusionsGeospatial mobility, sexual concurrency, and higher HIV-risk partnerships significantly influence longitudinal CT and/or NG prevalence in East Africa.