Inclusion Criteria:

* Laboratory-confirmed diagnosis of SARS-CoV-2 pneumonia
* Currently hospitalized with COVID-19
* Symptomatic fever, cough and/or dyspnea for < 9 days
* Patient or legal/authorized representative can understand and sign the study informed consent document
* Able to be positioned on a linear-accelerator couch for Radiation Therapy delivery
* And at least one of the following risk factors for significant pulmonary compromise:

1. Fever > 102 degrees Fahrenheit during index admission
2. Respiratory rate of ≥ 26 / minute within 24 hours of screening
3. SpO2 ≤ 95% on room air within 24 hours of screening
4. Any patient requiring 4 L/min oxygen therapy to maintain SpO2 >93% within 24 hours of screening
5. Ratio of partial pressure of arterial oxygen to fraction of inspired air < 320.
* Patients may be enrolled on this trial while concurrently enrolled on other COVID-19 clinical trials.

Exclusion Criteria:

* Currently requiring mechanical ventilation
* Prior thoracic radiotherapy, with the exception of the following:

1. Breast or post-mastectomy chest wall radiation (without regional nodal irradiation) may be included at the discretion of the site primary investigator, and
2. Thoracic skin radiation therapy (without regional nodal irradiation) is allowed.
* Known hereditary syndrome with increased sensitivity to radiotherapy, including ataxia-telangiectasia, xeroderma pigmentosum, and Nijmegen Breakage Syndrome
* Known prior systemic use of the following drugs: Bleomycin, Carmustine, Methotrexate, Busulfan, Cyclophosphamide, or Amiodarone
* History of or current diagnosis of pulmonary fibrosis, or an alternative pulmonary condition responsible for significant lung compromise at the discretion of the site primary investigator
* History of lung lobectomy or pneumonectomy
* Known history of pulmonary sarcoidosis, Wegener's granulomatosis, systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis, polymyositis/dermatomyositis, Sjögren's syndrome, mixed connective tissue disease, Churg-Strauss syndrome, Goodpasture's syndrome, or ankylosing spondylitis.
* Symptomatic congestive heart failure within the past 6 months including during current hospitalization
* History of recent or current malignancy receiving any cytotoxic chemotherapy or immunotherapy within the past 6 months.
* History of bone marrow transplantation.
* History of any solid organ transplant (renal, cardiac, liver, lung) requiring immunosuppressive therapy.
* Females who are pregnant or breast feeding.
* Inability to undergo radiotherapy for any other medical or cognitive issues.