Safety and Efficacy of Rayaldee for Treating Mild to Moderate COVID-19

Inclusion Criteria: 1. Male or female ≥18 years of age 2. Confirmed within the past 3 days to have SARS-CoV-2 infection as evidenced by a positive nasopharyngeal swab test using RT-PCR or any substitutable FDA-authorized diagnostic test 3. Confirmed to have only mild or moderate COVID-19 based on the first of the patient reported scores obtained during screening which meets the criterion a FLU-PRO Plus© score of ≥ 1.5 for each of the chest/respiratory and body/systemic domains, and the absence of clinical signs indicative of more severe disease (eg, oxygen saturation \< 94% on room air or respiration rate \> 30 bpm) 4. Represents on self-assessment that the current COVID-19 symptoms are not consistent with usual health and that they are the same or worse than on the previous day 5. Willing to limit the use of vitamin D therapies or supplements except for normally fortified food products (eg, milk) during the course of the 6-week study 6. Must demonstrate the ability to comply with all study requirements 7. Must be without any disease state or physical condition that might impair evaluation of safety or which, in the investigator's opinion, would interfere with study participation. Exclusion Criteria: 1. Clinical signs indicative of severe or critical COVID-19 disease (eg, oxygen saturation \< 94% on room air or respiration rate \> 30 bpm) 2. Pregnant or lactating women who are breastfeeding 3. Use of systemic glucocorticoid medications in the last six months 4. Recent history (previous 12 months) of primary hyperparathyroidism, kidney stones, hypercalciuria and/or hypercalcemia 5. History of a chronic granuloma-forming disease (eg, sarcoidosis) 6. History of tuberculosis or histoplasmosis 7. History of chronic liver disease 8. History (previous 12 months) of cardiac event indicative of chronic cardiovascular diseases including congestive heart failure, poorly controlled hypertension and arrhythmias 9. History in the past five years of multiple myeloma or carcinoma of the breast, lung or prostate 10. Any surgical or medical condition which might significantly alter the absorption, distribution, metabolism, or excretion of vitamin D or 25-hydroxyvitamin D (25D) (eg, small bowel resection, history of Crohn's disease or ulcerative colitis) 11. Ongoing treatment with thiazide diuretics 12. History of hyperphosphatemia, hyperuricemia and gout 13. Renal impairment measured as eGFR\< 15 mL/min/1.73m² on serum creatinine in the last three months 14. Serum calcium ≥9.8 mg/dL in the last three months 15. Evidence of existing or impending dehydration 16. Known or suspected to have hypersensitivity to any of the constituents of the study drug 17. Currently participating in, or have participated in, an interventional/investigational study within 30 days prior to study screening.