Heterogeneity in HIV/STI Prevalence, Testing, and PrEP Use among Transgender and Non-binary People and their Partners in the US

Diana Tordoff | 2022

Advisor: Ann Duerr

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Transgender and non-binary (TNB) people in the U.S. are disproportionately impact by HIV and sexually transmitted infections (STIs). As a result of socio-structural stigma, institutional barriers, and fear of mistreatment, and discrimination, TNB people experience significant barriers to engaging in health care, including HIV/STI prevention. In addition, the HIV/STI prevalence and behaviors of their sex partners may play an important role in TNB people’s acquisition of HIV/STIs, and are important for understanding patterns of HIV/STI acquisition and transmission. To improve our understanding of the epidemiology of HIV/STIs, testing, and pre-exposure prophylaxis (PrEP) use among TNB people and their partners, we used three approaches to elucidate heterogeneity within the TNB community based on geography, gender identity and race/ethnicity, and gender of sex partners. First, we applied a Bayesian hierarchical spatial small area estimation model to data from the 2015 US Transgender Survey (USTS), a large national internet-based survey of 26,100 TNB adults, to estimate the county- and state-level proportion of TNB adults who have tested for HIV. Second, we pooled data from five 2017-2021 Washington State HIV/STI surveillance data sources to obtain a large and diverse sample of TNB people as well as cisgender people who reported having a TNB partner in the last year. Using these data we applied descriptive quantitative intersectionality methods to examine difference in HIV/STI testing, PrEP use, healthcare access, and socio-structural factors associated with poverty within TNB communities in Washington state and describe the epidemiology of HIV/STIs and prevention utilization among the partners of TNB people. Third, we developed a novel mathematical model of HIV transmission that more accurately represents the sexual network of TNB people, including trans-trans partnerships, and, for the first time, includes transgender men and non-binary people. We used this model to simulate the potential impact of increasing access to PrEP and more frequent HIV testing among TNB people in the US. We found that there was significant heterogeneity in HIV/STI prevalence and prevention utilization among TNB and their partners across a number of axes of experience, including geography, race/ethnicity, gender identity, sexual minority status, and gender of sex partners. Our findings highlight the need for trans-inclusive models of HIV/STI prevention and PrEP delivery that address multilevel barriers rooted in cissexism and structural racism.