The COVID-19 pandemic has created unique challenges for vulnerable populations. As part of the mission of the OHDRC, we have maintained continuous community engagement and partnerships aimed at finding ways to reduce the impact of obesity and related chronic diseases. With the advent of COVID-19, we were quickly able to leverage these long-standing and trusting relationships to learn how COVID-19 was perceived by the residents of our partnering vulnerable communities. Through ongoing community dialogue, we know that there are substantial differences in how residents in our partner communities understand and act upon COVID-19 guidance, perhaps contributing to the alarming disparities in COVID-19 outcomes. Overall, residents feel that COVID-19 is making marginalized communities even more marginalized. In this environment, it is vital that we find ways to improve COVID-19 vaccination, testing and follow-up care through collaboration with community partners. The overall goal of this proposal, COVID-19 Testing Model for Vulnerable Populations: Revision to Address Vaccine Hesitancy and Uptake, is to expand the RADx-UP Revision to the NIMHD (U54) UAB Obesity Health Disparities Research Center (OHDRC) to explore COVID-19 vaccine hesitancy in Jefferson County, Alabama and based on these results, design and integrate a multi-level vaccine hesitancy component into the existing parent RADx-UP grant. The overall goal of the parent grant, COVID-19 Testing Model for Vulnerable Populations: From Community Engagement to Follow-Up, is to implement a three-component mobile community-based testing model and evaluate its impact for improved reach, access, acceptance, uptake, and appropriate follow-up to COVID-19 testing. We will utilize the infrastructure of the existing project, including the Scientific Advisory Board (SAB) and Community Advisory Board (SAB) as well as a strong Partner Council of community organizations. We will also partner with the Alabama Community Engagement Alliance against COVID-19 (AL CEAL), which has built an extensive infrastructure across Alabama. This study will use the results of work on COVID-19 vaccine hesitancy and uptake in Alabama conducted by AL CEAL and will conduct further qualitative and quantitative assessments to explore deep vaccine hesitancy to design and evaluate a multi-level intervention to decrease vaccine hesitancy that can be integrated into existing CEAL and RADx-UP community-level and individual-level efforts, while also addressing key systems-level influences, churches and primary care clinics.