a subject who meets any of the following criteria must not be entered into the randomized treatment in the study: 1. where, in the opinion of the investigator, participation in this study will not be in the best interest of the subject, or any other circumstances that prevent the subject from participating in the study safely 2. subjects with infection requiring oxygen support, invasive or non-invasive ventilator support, extracorporeal membrane oxygenation (ecmo) or shock requiring vasopressor support. 3. current known pneumonia based on x-ray or computed tomography (ct) scan or history of pneumonia within 3 months before screening. 4. requiring hospitalization for the treatment of covid-19 5. subjects who have received any dose of vaccine for covid-19 6. prolonged qt, defined as qtcf ≥ 450 milliseconds for men and as qtcf ≥ 470 milliseconds for women 7. history of known severely reduced left ventricular (lv) function (ejection fraction \< 30 %) 8. requires icu care for management of ongoing clinical status. 9. known allergy or hypersensitivity to nitric oxide nasal spray. 10. history of known severe renal impairment \[creatinine clearance (crcl) \< 30 ml/min\] or having received continuous renal replacement therapy, hemodialysis or peritoneal dialysis; 11. asthma, allergic rhinitis or chronic obstructive lung disease 12. psychiatric disease that is not well controlled (controlled defined as stable on a regimen for more than one year). 13. pregnant or lactating women; 14. having used nitric oxide nasal spray or participated in any other interventional drug clinical study within 30 days prior to first dose of study drug. 15. subjects who have received hydroxychloroquine within 7 days before screening or subjects who require hydrochloroquine treatment. 16. subjects who have received intranasal medication/treatment within 7 days before screening or subjects who require use of any intranasal medication. 17. subjects who have received medications with antiviral effect such as remdesivir, favipiravir, oseltamivir, ivermectin or inhaled corticosteroids within 7 days before screening or subjects who require use of any of these medications 18. subjects using nitric oxide donor agents such as prilocaine, sodium nitroprusside and nitroglycerine duration of study participation: the anticipated maximum total study duration

a subject who meets any of the following criteria must not be entered into the randomized treatment in the study: 1. where, in the opinion of the investigator, participation in this study will not be in the best interest of the subject, or any other circumstances that prevent the subject from participating in the study safely 2. subjects with infection requiring oxygen support, invasive or non-invasive ventilator support, extracorporeal membrane oxygenation (ecmo) or shock requiring vasopressor support. 3. current known pneumonia based on x-ray or computed tomography (ct) scan or history of pneumonia within 3 months before screening. 4. requiring hospitalization for the treatment of covid-19 5. subjects who have received any dose of vaccine for covid-19 6. prolonged qt, defined as qtcf ≥ 450 milliseconds for men and as qtcf ≥ 470 milliseconds for women 7. history of known severely reduced left ventricular (lv) function (ejection fraction \< 30 %) 8. requires icu care for management of ongoing clinical status. 9. known allergy or hypersensitivity to nitric oxide nasal spray. 10. history of known severe renal impairment \[creatinine clearance (crcl) \< 30 ml/min\] or having received continuous renal replacement therapy, hemodialysis or peritoneal dialysis; 11. asthma, allergic rhinitis or chronic obstructive lung disease 12. psychiatric disease that is not well controlled (controlled defined as stable on a regimen for more than one year). 13. pregnant or lactating women; 14. having used nitric oxide nasal spray or participated in any other interventional drug clinical study within 30 days prior to first dose of study drug. 15. subjects who have received hydroxychloroquine within 7 days before screening or subjects who require hydrochloroquine treatment. 16. subjects who have received intranasal medication/treatment within 7 days before screening or subjects who require use of any intranasal medication. 17. subjects who have received medications with antiviral effect such as remdesivir, favipiravir, oseltamivir, ivermectin or inhaled corticosteroids within 7 days before screening or subjects who require use of any of these medications 18. subjects using nitric oxide donor agents such as prilocaine, sodium nitroprusside and nitroglycerine duration of study participation: the anticipated maximum total study duration

a subject who meets any of the following criteria must not be entered into the randomized treatment in the study: where, in the opinion of the investigator, participation in this study will not be in the best interest of the subject, or any other circumstances that prevent the subject from participating in the study safely subjects with infection requiring oxygen support, invasive or non-invasive ventilator support, extracorporeal membrane oxygenation (ecmo) or shock requiring vasopressor support. current known pneumonia based on x-ray or computed tomography (ct) scan or history of pneumonia within 3 months before screening. requiring hospitalization for the treatment of covid-19 subjects who have received any dose of vaccine for covid-19 prolonged qt, defined as qtcf ≥ 450 milliseconds for men and as qtcf ≥ 470 milliseconds for women history of known severely reduced left ventricular (lv) function (ejection fraction < 30 %) requires icu care for management of ongoing clinical status. known allergy or hypersensitivity to nitric oxide nasal spray. history of known severe renal impairment [creatinine clearance (crcl) < 30 ml/min] or having received continuous renal replacement therapy, hemodialysis or peritoneal dialysis; asthma, allergic rhinitis or chronic obstructive lung disease psychiatric disease that is not well controlled (controlled defined as stable on a regimen for more than one year). pregnant or lactating women; having used nitric oxide nasal spray or participated in any other interventional drug clinical study within 30 days prior to first dose of study drug. subjects who have received hydroxychloroquine within 7 days before screening or subjects who require hydrochloroquine treatment. subjects who have received intranasal medication/treatment within 7 days before screening or subjects who require use of any intranasal medication. subjects who have received medications with antiviral effect such as remdesivir, favipiravir, oseltamivir, ivermectin or inhaled corticosteroids within 7 days before screening or subjects who require use of any of these medications subjects using nitric oxide donor agents such as prilocaine, sodium nitroprusside and nitroglycerine duration of study participation: the anticipated maximum total study duration

a subject who meets any of the following criteria must not be entered into the randomized treatment in the study: where, in the opinion of the investigator, participation in this study will not be in the best interest of the subject, or any other circumstances that prevent the subject from participating in the study safely subjects with infection requiring oxygen support, invasive or non-invasive ventilator support, extracorporeal membrane oxygenation (ecmo) or shock requiring vasopressor support. current known pneumonia based on x-ray or computed tomography (ct) scan or history of pneumonia within 3 months before screening. requiring hospitalization for the treatment of covid-19 subjects who have received any dose of vaccine for covid-19 prolonged qt, defined as qtcf ≥ 450 milliseconds for men and as qtcf ≥ 470 milliseconds for women history of known severely reduced left ventricular (lv) function (ejection fraction < 30 %) requires icu care for management of ongoing clinical status. known allergy or hypersensitivity to nitric oxide nasal spray. history of known severe renal impairment [creatinine clearance (crcl) < 30 ml/min] or having received continuous renal replacement therapy, hemodialysis or peritoneal dialysis; asthma, allergic rhinitis or chronic obstructive lung disease psychiatric disease that is not well controlled (controlled defined as stable on a regimen for more than one year). pregnant or lactating women; having used nitric oxide nasal spray or participated in any other interventional drug clinical study within 30 days prior to first dose of study drug. subjects who have received hydroxychloroquine within 7 days before screening or subjects who require hydrochloroquine treatment. subjects who have received intranasal medication/treatment within 7 days before screening or subjects who require use of any intranasal medication. subjects who have received medications with antiviral effect such as remdesivir, favipiravir, oseltamivir, ivermectin or inhaled corticosteroids within 7 days before screening or subjects who require use of any of these medications subjects using nitric oxide donor agents such as prilocaine, sodium nitroprusside and nitroglycerine duration of study participation: the anticipated maximum total study duration