1. has a who clinical progression scale (whob 2020) score of '4' or higher at screening or enrollment 2. previous hypersensitivity or allergic reactions to naltrexone 3. women who are pregnant or lactating or expecting to become pregnant 4. drugs of abuse screen positive for opiates 5. patients with history of moderate to severe renal impairment (estimated creatinine clearance \< 50 ml/min) or hepatic impairment (child-pugh c) 6. serum alt or ast value \> 3 times the uln at screening 7. serum creatinine value \> 2 times the uln at screening, or requires renal dialysis 8. hematology results at screening showing any one of the following: wbc \<2000 cells/mm3 or platelet count \<100,000 cells/mm3 or hemoglobin \<8.5 gm/dl 9. currently receiving chronic daily opioid therapy 10. use of tocilizumab or other immunomodulator therapy directed to treatment or prevention of covid-19 11. history of active substance abuse within the 2 years prior to screening 12. participation in another clinical trial investigating a treatment for covid-19 13. currently hospitalized or under immediate consideration for hospitalization (for any medical reason) at the screening visit 14. at screening, has new onset of dyspnea (shortness of breath) or, if previously diagnosed with a chronic lung condition, the severity of dyspnea has increased over patient's historical baseline condition (increased dyspnea should be present continually and not intermittent) 15. measurement of oxygen saturation at screening is \< 94% on ambient room air 16. shares a household with a patient currently enrolled in this protocol 17. patients who refuse biomarker blood draws

1. has a who clinical progression scale (whob 2020) score of '4' or higher at screening or enrollment 2. previous hypersensitivity or allergic reactions to naltrexone 3. women who are pregnant or lactating or expecting to become pregnant 4. drugs of abuse screen positive for opiates 5. patients with history of moderate to severe renal impairment (estimated creatinine clearance \< 50 ml/min) or hepatic impairment (child-pugh c) 6. serum alt or ast value \> 3 times the uln at screening 7. serum creatinine value \> 2 times the uln at screening, or requires renal dialysis 8. hematology results at screening showing any one of the following: wbc \<2000 cells/mm3 or platelet count \<100,000 cells/mm3 or hemoglobin \<8.5 gm/dl 9. currently receiving chronic daily opioid therapy 10. use of tocilizumab or other immunomodulator therapy directed to treatment or prevention of covid-19 11. history of active substance abuse within the 2 years prior to screening 12. participation in another clinical trial investigating a treatment for covid-19 13. currently hospitalized or under immediate consideration for hospitalization (for any medical reason) at the screening visit 14. at screening, has new onset of dyspnea (shortness of breath) or, if previously diagnosed with a chronic lung condition, the severity of dyspnea has increased over patient's historical baseline condition (increased dyspnea should be present continually and not intermittent) 15. measurement of oxygen saturation at screening is \< 94% on ambient room air 16. shares a household with a patient currently enrolled in this protocol 17. patients who refuse biomarker blood draws

has a who clinical progression scale (whob 2020) score of '4' or higher at screening or enrollment previous hypersensitivity or allergic reactions to naltrexone women who are pregnant or lactating or expecting to become pregnant drugs of abuse screen positive for opiates patients with history of moderate to severe renal impairment (estimated creatinine clearance < 50 ml/min) or hepatic impairment (child-pugh c) serum alt or ast value > 3 times the uln at screening serum creatinine value > 2 times the uln at screening, or requires renal dialysis hematology results at screening showing any one of the following: wbc <2000 cells/mm3 or platelet count <100,000 cells/mm3 or hemoglobin <8.5 gm/dl currently receiving chronic daily opioid therapy use of tocilizumab or other immunomodulator therapy directed to treatment or prevention of covid-19 history of active substance abuse within the 2 years prior to screening participation in another clinical trial investigating a treatment for covid-19 currently hospitalized or under immediate consideration for hospitalization (for any medical reason) at the screening visit at screening, has new onset of dyspnea (shortness of breath) or, if previously diagnosed with a chronic lung condition, the severity of dyspnea has increased over patient's historical baseline condition (increased dyspnea should be present continually and not intermittent) measurement of oxygen saturation at screening is < 94% on ambient room air shares a household with a patient currently enrolled in this protocol patients who refuse biomarker blood draws

has a who clinical progression scale (whob 2020) score of '4' or higher at screening or enrollment previous hypersensitivity or allergic reactions to naltrexone women who are pregnant or lactating or expecting to become pregnant drugs of abuse screen positive for opiates patients with history of moderate to severe renal impairment (estimated creatinine clearance < 50 ml/min) or hepatic impairment (child-pugh c) serum alt or ast value > 3 times the uln at screening serum creatinine value > 2 times the uln at screening, or requires renal dialysis hematology results at screening showing any one of the following: wbc <2000 cells/mm3 or platelet count <100,000 cells/mm3 or hemoglobin <8.5 gm/dl currently receiving chronic daily opioid therapy use of tocilizumab or other immunomodulator therapy directed to treatment or prevention of covid-19 history of active substance abuse within the 2 years prior to screening participation in another clinical trial investigating a treatment for covid-19 currently hospitalized or under immediate consideration for hospitalization (for any medical reason) at the screening visit at screening, has new onset of dyspnea (shortness of breath) or, if previously diagnosed with a chronic lung condition, the severity of dyspnea has increased over patient's historical baseline condition (increased dyspnea should be present continually and not intermittent) measurement of oxygen saturation at screening is < 94% on ambient room air shares a household with a patient currently enrolled in this protocol patients who refuse biomarker blood draws

1. has a who clinical progression scale (whob 2020) score of '4' or higher at screening or enrollment 2. previous hypersensitivity or allergic reactions to naltrexone 3. women who are pregnant or lactating or expecting to become pregnant 4. drugs of abuse screen positive for opiates 5. patients with history of moderate to severe renal impairment (estimated creatinine clearance < 50 ml/min) or hepatic impairment (child-pugh c) 6. serum alt or ast value > 3 times the uln at screening 7. serum creatinine value > 2 times the uln at screening, or requires renal dialysis 8. hematology results at screening showing any one of the following: wbc <2000 cells/mm3 or platelet count <100,000 cells/mm3 or hemoglobin <8.5 gm/dl 9. currently receiving chronic daily opioid therapy 10. use of tocilizumab or other immunomodulator therapy directed to treatment or prevention of covid-19 11. history of active substance abuse within the 2 years prior to screening 12. participation in another clinical trial investigating a treatment for covid-19 13. currently hospitalized or under immediate consideration for hospitalization (for any medical reason) at the screening visit 14. at screening, has new onset of dyspnea (shortness of breath) or, if previously diagnosed with a chronic lung condition, the severity of dyspnea has increased over patient's historical baseline condition (increased dyspnea should be present continually and not intermittent) 15. measurement of oxygen saturation at screening is < 94% on ambient room air 16. shares a household with a patient currently enrolled in this protocol 17. patients who refuse biomarker blood draws

1. has a who clinical progression scale (whob 2020) score of '4' or higher at screening or enrollment 2. previous hypersensitivity or allergic reactions to naltrexone 3. women who are pregnant or lactating or expecting to become pregnant 4. drugs of abuse screen positive for opiates 5. patients with history of moderate to severe renal impairment (estimated creatinine clearance < 50 ml/min) or hepatic impairment (child-pugh c) 6. serum alt or ast value > 3 times the uln at screening 7. serum creatinine value > 2 times the uln at screening, or requires renal dialysis 8. hematology results at screening showing any one of the following: wbc <2000 cells/mm3 or platelet count <100,000 cells/mm3 or hemoglobin <8.5 gm/dl 9. currently receiving chronic daily opioid therapy 10. use of tocilizumab or other immunomodulator therapy directed to treatment or prevention of covid-19 11. history of active substance abuse within the 2 years prior to screening 12. participation in another clinical trial investigating a treatment for covid-19 13. currently hospitalized or under immediate consideration for hospitalization (for any medical reason) at the screening visit 14. at screening, has new onset of dyspnea (shortness of breath) or, if previously diagnosed with a chronic lung condition, the severity of dyspnea has increased over patient's historical baseline condition (increased dyspnea should be present continually and not intermittent) 15. measurement of oxygen saturation at screening is < 94% on ambient room air 16. shares a household with a patient currently enrolled in this protocol 17. patients who refuse biomarker blood draws