Mobility and its Effects on HIV Acquisition and Treatment Engagement: Recent Theoretical and Empirical Advances.

PURPOSE OF REVIEW: We reviewed literature across multiple disciplines to describe issues with the measurement of population mobility in HIV research and to summarize evidence of causal pathways linking mobility to HIV acquisition risks and treatment engagement, with a focus on sub-Saharan Africa. RECENT FINDINGS: While the literature on mobility and HIV remains hampered by problems and inconsistency in measures of mobility, the recent research reveals a turn towards a greater attentiveness to measurement and gender. Theoretical and heuristic models for the study of mobility and HIV acquisition and treatment outcomes have been published, but few studies have used longitudinal designs with clear ascertainment of exposures and outcomes for measurement of causal pathways. Notwithstanding these limitations, evidence continues to accumulate that mobility is linked to higher HIV incidence, and that it challenges optimal treatment engagement. Gender continues to be important: while men are more mobile than women, women's mobility particularly heightens their HIV acquisition risks. Recent large-scale efforts to find, test, and treat the individuals in communities who are most at risk of sustaining local HIV transmission have been severely challenged by mobility. Novel interventions, policies, and health systems improvements are urgently needed to fully engage mobile individuals in HIV care and prevention. Interventions targeting the HIV prevention and care needs of mobile populations remain few in number and urgently needed.