Hospital Revitalization Act of 2021 This bill establishes a program within the Department of Health and Human Services (HHS) to provide grants and low-interest loans to hospitals that, prior to 2020, were small, had poor financial indicators, and served a high number of patients with public insurance. Hospitals may use grants to construct and modernize their facilities, including rural health clinics, off-site outpatient departments, and other facilities that are not physically part of the hospital building. HHS must develop criteria to prioritize grant recipients based on, for example, the age and physical state of the hospital and whether the hospital is located in an area with a shortage of health care providers.