Causes and consequences of heterogeneity in HIV epidemics

We are working to understand the causes and consequences of heterogeneity in the risks of HIV/STI acquisition and transmission. Heterogeneity in risks may reflect variability in biology, individual-level behavior, partnership-level features and sexual networks, and structural pathways that interact and modify each of the former. Our goal is to creatively explore and disentangle the role of – and interactions between – various factors in establishing and sustaining HIV/STI epidemics. We work with different types of data and different types of statistical and mathematical models to answer our research questions.

Our work includes examining approaches to quantify the relative “contribution” of specific risk factors, or unmet needs (prevention and treatment gaps) across subsets of a population, to onward HIV/STI transmission in Sub-Saharan Africa. For example, we are conducting several projects related to the transmission population attributable fraction (tPAF), such as examining the determinants of the tPAF and how model structure and heterogeneity influence tPAF projections.

Our work on heterogeneity in risks by age, sex work hotspots, and sexual networks include the CIHR-funded Transitions study. Transitions is an observational and mathematical modeling study co-led in partnership with Dr. Marissa Becker and the Centre for Global Public Health at the University of Manitoba, Kenya HIV Technical Support Unit, Government of Kenya National AIDS and STIs Control Programme, and the Ukranian Institute of Social Research. Examples of findings to date include: