Evaluating the biomedical and behavioral drivers of HIV incidence decline in adolescent girls and young women in Uganda: A mathematical modeling study

Abstract

Background: HIV incidence among adolescent girls and young women (AGYW) in eastern and southern Africa has declined substantially over the past two decades. These declines are often attributed to biomedical HIV prevention strategies, though concurrent changes in sexual behavior may also contribute. We evaluated the contributions of biomedical and behavioral drivers to historical incidence decline in AGYW and projected their impact on incidence trajectories over the next 30 years. Methods and findings: We conducted a mathematical modeling study using data from the Rakai Community Cohort Study (RCCS), an open, population-based cohort of adults aged 15–49 years in 30 communities in Rakai, Uganda. We used an agent-based HIV-1 transmission model calibrated to cohort data to estimate HIV incidence trends among AGYW, aged 15–24, and to quantify the independent and combined effects of antiretroviral therapy (ART), voluntary medical male circumcision (VMMC), and changes in age at first sex (AFS). Conclusions: Both biomedical HIV interventions and broader behavioral changes contributed to declines in HIV incidence among AGYW. Sustaining continued incidence declines in young women will require maintaining both the protective changes in sexual behaviors and effective biomedical interventions. Why was this study done?: What did the researchers do and find?: What do these findings mean?: Using mathematical modeling, Adam Akullian and colleagues estimate that increasing age at first sex is a key driver of the decline in HIV incidence among young women in the Rakai Community Cohort Study in Uganda.

Original publication: PLOS Medicine (2026-03-25). Source. Source DOI: 10.1371/journal.pmed.1004993.