Migration and risk of HIV acquisition in Rakai, Uganda: a population-based cohort study

BACKGROUND: In sub-Saharan Africa, migrants typically have higher HIV prevalence than non-migrants; however, whether HIV acquisition precedes or follows migration is generally unknown. Here, we assessed risk of HIV following migration. METHODOLOGY: We assessed the association between migration and HIV acquisition using prospective data from HIV-negative participants aged 15–49 enrolled in an open population-based cohort in Rakai, Uganda between 1999 and 2015. Individuals were classified as recent in-migrants if they moved into study communities within the prior two years, non-recent migrants (>2 years in community), or permanent residents with no migration history. Poisson regression was used to estimate incidence rate ratios (IRR) of HIV associated with residence status with adjustment for demographics, sexual behaviors, and time. RESULTS: 15,187 HIV-negative individuals were followed for 89,292 person-years of whom 29% (n=4451) were ever in-migrants. There were 841 incident HIV events, including 243 (29%) among inmigrants. Relative to permanent residents, HIV incidence was significantly increased among recent inmigrants among women (1.92/100 pys in recent migrants vs. 0.93/100 pys in permanent residents; adjIRR=1.74, 95%CI: 1.12–2.71) and men (1.52/100 pys vs 0.84/100 pys; adjIRR=1.74, 95%CI: 1.12–2.71), but was not among non-recent in-migrants. HIV incidence declined over time with scale-up of combination HIV prevention among permanent residents and non-recent in-migrants, but was unchanged among recent in-migrants. CONCLUSION: The first two years after migration are associated with increased risk of HIV acquisition. Findings highlight the need for prevention programs focused on migrants to reduce HIV incidence in sub-Saharan Africa.