Project Summary This proposal addresses NIMH’s call for HIV vaccine preparedness and “HIV vaccine-related” communication research (Notice of Special Interest NOT-MH-21-105). Though vaccines may be years away, the NOSI recognizes that the time to conduct rigorous HIV vaccine communication research is now – to advance the basic science of effective HIV vaccine messaging and get ahead of misinformation. HIV disproportionately impacts young Black women living in the Southern US. Black women make up 13% of the female population in the US, yet make up 54% of new HIV infections among women in the US. These disparities are most extreme in the South, where black women account for 72% of new HIV infections among women. These data highlight the urgent need to develop and scale-up biomedical HIV prevention strategies centered on the unique needs of Black women in the South. Herein, we propose to develop and test a multi- component communications intervention to promote uptake of a future HIV vaccine, as part of a comprehensive set of strategies for HIV prevention, among Black women ages 18–34 in the South. Our diverse team of HIV clinicians, behavioral scientists and health communication experts includes faculty from Texas Southern University, the 2nd largest Historically Black College and University (HBCU) in the US. This five-year study will take place in Houston, Texas, an epicenter of the HIV epidemic in the US South. We will use community based participatory research methods (CBPR) and Community Engagement Studios to engage young Black women in co-creating and testing communication content across multiple components (i.e., words, graphics, videos). To increase uptake of a future HIV vaccine, we will conduct the following aims: 1) Assess barriers and facilitators to uptake of a future HIV vaccine within the larger family of biomedical HIV prevention tools, 2) Co-create theory-based message features (i.e., strategic word choice/ framing), graphics, and short videos (30-120 seconds) for uptake of a future HIV vaccine. Theory-based features include enhanced active choice, protective agency assignment, autonomy restoration, anticipated affect. 3) Evaluate the effect of different theory-based message features, graphics and videos on HIV vaccine and prevention intention. We will evaluate effects in three separate randomized trials of young Black women. This proposal takes a rigorous approach to understanding the basic behavioral science of HIV vaccine communication. Communications research is needed to understand how to develop messages that address distinct barriers to seeking out HIV prevention (i.e., stigma, discrimination, medical mistrust, low risk perception, lack of awareness or knowledge) and at the same time, leverage personal and social factors that resonate with Black women (e.g., social networks, peer structures, and images and narratives that tap into the lived experiences of Black women). If successful, this model of message design may translate ...