2025 Theses Doctoral

Unpacking the HIV epidemic among people on the move in Uganda: actionable evidence for an equitable response

Khalifa, Aleya

Mobility – from overnight travel to permanent migration – can reduce service access and increase HIV risk in sub-Saharan Africa (SSA), influencing population-level HIV transmission as countries strive to end the epidemic by 2030. HIV programs must address the needs of mobile populations, yet mobility is a complex and multifaceted phenomenon that influences HIV outcomes in diverse ways. Through a systematic scoping review of mobility measures and two empirical studies conducted in southern Uganda, this dissertation examines HIV outcomes among distinct mobile subclasses and their networks to identify gaps and opportunities in the HIV response.

First, I introduce mobility’s significance in the African HIV epidemic and gaps in the evidence base. Chapter 2 (Aim 1) presents findings from a systematic scoping review of mobility measures used in HIV research across SSA in the past decade. Chapters 3 and 4 present empirical studies investigating the relationship between various forms of mobility and HIV outcomes that fuel HIV transmission. In Chapter 3 (Aim 2), I use latent class analysis to identify subclasses of people on the move, characterizing mobility and its association with HIV outcomes along the prevention, care, and treatment cascade. In Chapter 4 (Aim 3), I use a case-control study to examine the impacts of migration and travel on HIV acquisition among individuals and their sexual partners. Finally, I summarize the dissertation’s overarching findings and discuss implications for future research and the HIV response.

Aim 1 identifies spatial, social, and temporal metrics for describing forms of mobility that may relate differently to HIV outcomes, demonstrating the need for detailed and comprehensive mobility measurement in HIV research. Applying these metrics, Aim 2 uncovers ten latent classes of migration and travel, defined by duration, distance, and motivations for movement. Each class reveals gendered associations with HIV outcomes. Some mobile-gender groups, like women moving between households in the community, are more likely to be living with HIV or viremic, requiring sustained access to HIV services for them and their partners, while others may be underserved in specific interventions, like young women traveling for opportunity with low testing coverage. Finally, Aim 3 underscores the need for HIV prevention programs to tailor intervention strategies to highly mobile partners in high-risk sexual networks, especially women and sex workers. While individual mobility did not impact HIV acquisition, the role of partner mobility could be further explored by gender, mobile subclass, and partner type with more complete network data.

This dissertation demonstrates the heterogeneity of mobile populations and their gendered HIV risks. Local HIV programs can tailor interventions like pre-exposure prophylaxis, self-testing, and differentiated service delivery for antiretroviral treatment to specific subgroups, while HIV control efforts can identify and deliver services to high-risk mobile networks. To produce more actionable evidence for the epidemic, future research should: 1) develop multidimensional mobility measures, 2) improve representation of mobile populations, 3) conduct longitudinal analyses for causal inference, 4) examine causal pathways by which mobility increases HIV risk, and 5) integrate spatial and sexual network data to research HIV transmission dynamics. By embracing the complexity of human movement, this dissertation provides a methodological framework to understand how large-scale demographic processes, like mobility, challenge public health programs.