The Centers for Disease Control and Prevention (CDC) defines chronic conditions as those that last one year or more, require ongoing medical attention, or limit activities of daily living [1]. Approximately 60 % of United States (U.S.) adults live with a chronic condition such as cancer, diabetes, or heart, lung, kidney, or Alzheimer’s disease; 40 % live with multiple conditions [1]. Living with chronic conditions is associated with poorer quality of life, greater healthcare costs, and increased mortality [2]. Indeed, chronic conditions are the leading cause of disability and death and are drivers of the U.S.’s $4.1 trillion in annual healthcare expenses [1]. There also exists a bidirectional relationship between chronic conditions and disability, an umbrella term encompassing impairment, participation restriction, and activity limitation within personal and environmental contextual factors [3]. That is, disabilities may emerge from chronic conditions and those with disabilities may be at an increased risk of developing additional chronic conditions [4].

Chronic conditions [5], [6], and in particular, multi-morbidity (i.e., the coexistence of two or more chronic conditions) continue to be a leading risk factor for severe COVID-19 and poor outcomes that increases along with morbidity burden [7]. Thus, testing and vaccination for active disease are cornerstones of preventive behavior in those living with multiple chronic conditions. Those with chronic conditions likely present with greater rates of COVID-19 testing and vaccination, potentially due to increased engagement in preventive measures and fear of severe illness if infected [8], [9], [10], [11]. However, disability may introduce barriers [5], [12], making it difficult for those with chronic conditions to get tested and vaccinated. Additionally, challenges such as food insecurity [13], and issues accessing healthcare and transportation [14], were commonly encountered challenges in those with chronic conditions before the COVID-19 pandemic. Public health crises often exacerbate disparities, disproportionally affecting marginalized groups [15]. Thus, disability may have contributed to heightened challenges for those living with chronic conditions during the COVID-19 pandemic.

The Rapid Acceleration of Diagnostics-Underserved Population (RADx-UP) initiative was developed by the National Institutes of Health (NIH) to ensure COVID-19 testing access, with a focus on vulnerable communities [16]. Thus, RADx-UP is uniquely positioned to investigate chronic conditions, disability, and COVID-19 preventive behaviors. The objectives of this study were to assess the associations between: (1) chronic conditions and COVID-19 testing and vaccination and (2) chronic conditions and COVID-19-related challenges, with a focus on the interaction effect of disability.