Project Summary/Abstract The HIV Vaccine Trials Network (HVTN) has experienced significant challenges recruiting participants in early-stage HIV vaccine clinical trials. Formidable barriers to participation in HVTN preventive HIV early phase trials, including lack of HIV public urgency, numerous study visits, long-term follow-up, vaccine induced seropositivity and HIV stigma, have resulted in significant challenges enrolling participants into these trials. We will co-refine an existing media campaign, develop, test and evaluate a multilevel communication strategy to address some of these crucial concerns and strengthen our reputation of trustworthiness in marginalized communities disproportionately affected by HIV to increase their enrollment into early-stage HIV vaccine trials. Over the next 7 years, the HVTN will focus on the early phase trial program to move the field forward and to identify products efficiently and effectively for later efficacy testing. This will require the development and deployment of evidence-based strategies to combat misinformation and to strengthen community engagement. Our team and the clinical research sites in our Network have forged longstanding community partnerships with diverse stakeholders. During our phase 3 clinical trials for the US government-funded COVID-19 vaccine clinical trials we developed new strategies to supplement our community engagement program: (1) a consumer-driven marketing and advertising campaign; (2) virtual town halls and listening sessions; and (3) the use of expert panels to review protocols and provide guidance and direction. We will build on this work to inform our HIV strategy. We assembled an experienced team of diverse researchers to accomplish the following aims: 1) Identify components of an initial media campaign that impact HIV vaccine trial registration and develop a multilevel communication strategy; 2) Evaluate the impact of the multilevel communication strategy on Phase I HIV vaccine trial registration; and 3) Determine if the multilevel communication strategy generates public engagement with vaccines and vaccine trials. This project will be the first large-scale communication study conducted in the United States to improve community awareness of and engagement with HIV vaccine trial research. It will assess misinformation and engagement with this strategy to inform current and future HIV vaccine trials recruitment and is expected to have a positive health impact by establishing robust strategies to improve diversity, equity, and inclusion in Phase 1 preventive HIV vaccine trials.