Transgender women are at significantly higher risk of contracting HIV, yet analysis of the iPrEx study indicates use of pre-exposure prophylaxis (PrEP) had no effectiveness in preventing HIV in this group on an intention-to- treat basis. While significantly understudied, qualitative work suggests that trans women experience unique, trans-specific issues, including prioritization of hormone therapy and transition-related medical care over HIV prevention, and real and perceived trans-related stigma and discrimination in healthcare settings. The result is a significant group who is highly vulnerable to HIV infection and its negative health consequences, yet is less likely to benefit from PrEP. Research is urgently needed to understand how trans women perceive their HIV risk and make decisions about PrEP, as well as how healthcare providers address stigma and structural barriers to treatment, so that appropriate interventions can be developed. Utilizing perceptual mapping and vector modeling techniques, we will conduct a mixed methods study in San Francisco and Philadelphia combining in-depth qualitative methods with quantitative surveys to assess trans women's perceptions of PrEP, and get feedback on stigma and structural barriers to accessing healthcare from providers. Using vector message modeling, these maps will be used to identify specific message strategies to be embedded into larger interventions to address trans women's PrEP barriers and providers' barriers to treating trans women. 
Specific aims of the research are: 1: To create perceptual mapping survey instruments for trans women and healthcare providers to assess perceptions of PrEP, trans-related stigma, and barriers to healthcare. To accomplish this we will conduct focus groups (n=60) and interviews with healthcare providers (n=10) serving trans women and then develop perceptual mapping surveys based on findings; 2. To develop highly targeted messages to enhance PrEP decision-making in trans women and address structural barriers and beliefs in providers using perceptual mapping and vector modeling. To accomplish this aim we will conduct perceptual mapping surveys with trans women (n=100) and healthcare providers (n=50) and perform perceptual mapping and vector message modeling analysis to develop messages; 3. To assess the messages for cultural salience and get insight into acceptable communication channels and intervention activities to enhance decision making around PrEP use in HIV-negative trans women and address stigmatizing beliefs and structural barriers in providers. We will accomplish this by conducting focus groups with trans women (n=40) and interviews with providers (n=10) to get feedback on how messages would be best delivered in an intervention and analyze data to identify the most effective messages and delivery strategies. We expect our innovative methods will have wide application for designing effective, tailored messages to address barriers to PrEP and concerns about structural barriers to receiving healthcare, an important strategy for eliminating health disparities among an at- risk trans women.