Mexican and Central American men who have sex with men, sexual networks, and prevention hotspots in Los Angeles and San Bernardino Counties: The long-term aim of this research is to examine and map internal U.S. migration patterns, geo-referenced sexual networks, and HIV risk behavior among Mexican and Central American migrant men who have sex with men (MSM) in San Bernardino County, and identify key HIV prevention opportunities for these vulnerable populations. Results from this work have the potential to improve the health of mobile MSM as well as reduce transmission between linked geographical areas and prevent ongoing transmission within connected networks of migrants in their new destinations. Funding is provided by a grant from PIMSA: the Programa de Investigacion en Migration Y Salud, and internal UCSB grants (Regents’ Junior Faculty Fellowship and Academic Senate Faculty Research Grants)


Mathematical models to inform effective HIV self-testing strategies for men who have sex with men: This study will identify how rapid HIV self-testing strategies may impact HIV incidence in diverse populations of men who have sex with men (MSM). Results from our model will inform public health approaches to promote safe and effective home-use HIV testing strategies for MSM, such as whether home-use tests should only be promoted to supplement regular clinic-based tests. Our models are a practical and cost-effective way to examine the scenarios under which home-use testing can effectively reduce HIV incidence, and can support the design of clinical trials to test the effectiveness of home-use HIV testing interventions if such an initiative is warranted. Funding is provided by an NICHD R21 grant.


HIV and residential mobility among men who have sex with men over the lifecourse (the Mobile Study): Understanding men who have sex with men (MSM) migration patterns is critical for HIV surveillance and epidemiologic studies.  This information is critical in estimating HIV incidence and prevalence in MSM, and in assessing HIV prevention and care programs at the population-level.  We also need to understand when, where, and why MSM migrate, since residential mobility may be a significant factor in social, behavioral, and structural determinants of ongoing HIV transmission among MSM. This application proposes preliminary research designed to develop methods for estimating age-specific rates of migration to Seattle and HIV risk behavior among MSM.  Funding was provided by a University of Washington Center for AIDS Research New Investigator Award.


Migration to urban slums, sexual networks, and HIV in Ghana: The objective of this proposed work is to investigate the relationship between migration and HIV transmission. The hypothesis is that migration may be a significant determinant in HIV transmission because of the changes in timing and sequence of partnerships associated with migration and migrant behavior (empirically shown to exhibit risky sexual behavior). Thus migration may promote partnership concurrency that links individuals together to create large connected "components" in a network; such connected components allow a pathogen to travel rapidly and efficiently. Additionally, the longer the concurrent partnerships, the more time the pathogen has to spread throughout the population.

This hypothesis is being tested in Accra, Ghana with sexual network survey data (a retrospective relationship history calendar paired with migration and travel events), and will be used to drive a mathematical model of HIV transmission dynamics that can project the population level impacts of migration and sexual risk behavior. Funding was provided by a NIH K99/R00 career development award.