PROJECT SUMMARY/ABSTRACT This application is being submitted by the Colorado Clinical and Translational Sciences Institute (CCTSI; UL1 TR002535) in response to NOT-TR-20-028, Clinical and Translational Science Award (CTSA) Program Applications to Address 2019 Novel Coronavirus (COVID-19) Public Heath Need, and PA-18-591, Administrative Supplements to Existing NIH Grants and Cooperative Agreements. The COVID-19 pandemic has had unprecedented global impact. In some patients, SARS-CoV-2 infection leads to pneumonia, hyperinflammation, hypoxemic respiratory failure, acute respiratory distress syndrome, multiple organ dysfunction syndrome, and death. Although rapid advances have been made in identifying risk factors for severe COVID-19, there are currently no FDA-approved SARS-CoV-2 vaccines and only one emergency FDA- approved therapeutic (remdesivir). Most U.S. reports of COVID-19 clinical characteristics, treatments, and outcomes have been from a single hospital or health system or have presented only summary statistics obtained using a federated query design. Progress in this field is significantly impaired by the lack of a large, centralized multi-center, row-level, high-granularity clinical data resource with which to develop and test hypotheses and develop novel predictive and diagnostic computational tools. Therefore, there is an urgent public health need to build such a centralized resource. The Specific Aims for this UL1 Administrative Supplement are: 1. Build a deep and adaptive COVID-19 Clinical Data Mart. We will leverage the CCTSI Informatics Core and our enterprise data warehouse to create a COVID- 19 Data Mart that will include rich clinical data extracted from the electronic health records of large adult and pediatric health systems. We will harmonize the Data Mart to N3C's preferred common data model, the Observational Medical Outcomes Partnership (OMOP) model. 2. Share CCTSI COVID-19 case and control data with N3C. We will secure appropriate regulatory approvals and data transfer agreements and securely transfer harmonized COVID-19 data to N3C. 3. Co-Lead N3C Clinical Scenarios and Analytics. As one of the only practicing ICU physicians in the CTSA Informatics Enterprise Committee, the CCTSI Informatics Core Director, Dr. Tellen Bennett, will play a key role in N3C by engaging other clinician-scientists and leading prioritization and execution of clinical analyses. Taken together, these efforts will accelerate clinical and data science research toward the development of better therapeutic regimens and predictive and diagnostic tools in COVID-19.