* receiving or has received vasopressors during the current hospitalization; * more than 24 hours has elapsed since receipt of non-invasive ventilatory support (high-flow nasal cannula or continuous positive airway pressure or non-invasive ventilation) or invasive mechanical ventilation; * patient is expected to be discharged from the hospital in the next 24 hours; * more than 14 days have elapsed since the commencement of hospital admission with respiratory illness; * known glucose-6-phosphate dehydrogenase (g6pd) deficiency; * known sickle cell anemia * pregnancy or breastfeeding; * known allergy to vitamin c; * known kidney stones within the past 1 year; * received any intravenous vitamin c during this hospitalization unless incorporated in parenteral nutrition; * expected death or withdrawal of life-sustaining treatments within 48 hours; * previously enrolled in this study; * previously enrolled in a trial for which co-enrolment is not allowed (co- enrolment to be determined case by case). the trial has broad eligibility criteria and includes all covid-19 patients admitted to the hospital (e.g. hospital ward or the intensive care unit) who are not receiving vasopressors.

* receiving or has received vasopressors during the current hospitalization; * more than 24 hours has elapsed since receipt of non-invasive ventilatory support (high-flow nasal cannula or continuous positive airway pressure or non-invasive ventilation) or invasive mechanical ventilation; * patient is expected to be discharged from the hospital in the next 24 hours; * more than 14 days have elapsed since the commencement of hospital admission with respiratory illness; * known glucose-6-phosphate dehydrogenase (g6pd) deficiency; * known sickle cell anemia * pregnancy or breastfeeding; * known allergy to vitamin c; * known kidney stones within the past 1 year; * received any intravenous vitamin c during this hospitalization unless incorporated in parenteral nutrition; * expected death or withdrawal of life-sustaining treatments within 48 hours; * previously enrolled in this study; * previously enrolled in a trial for which co-enrolment is not allowed (co- enrolment to be determined case by case). the trial has broad eligibility criteria and includes all covid-19 patients admitted to the hospital (e.g. hospital ward or the intensive care unit) who are not receiving vasopressors.

- receiving or has received vasopressors during the current hospitalization; - more than 24 hours has elapsed since receipt of non-invasive ventilatory support (high-flow nasal cannula or continuous positive airway pressure or non-invasive ventilation) or invasive mechanical ventilation; - patient is expected to be discharged from the hospital in the next 24 hours; - more than 14 days have elapsed since the commencement of hospital admission with respiratory illness; - known glucose-6-phosphate dehydrogenase (g6pd) deficiency; - known sickle cell anemia - pregnancy or breastfeeding; - known allergy to vitamin c; - known kidney stones within the past 1 year; - received any intravenous vitamin c during this hospitalization unless incorporated in parenteral nutrition; - expected death or withdrawal of life-sustaining treatments within 48 hours; - previously enrolled in this study; - previously enrolled in a trial for which co-enrolment is not allowed (co- enrolment to be determined case by case). the trial has broad eligibility criteria and includes all covid-19 patients admitted to the hospital (e.g. hospital ward or the intensive care unit) who are not receiving vasopressors.

- receiving or has received vasopressors during the current hospitalization; - more than 24 hours has elapsed since receipt of non-invasive ventilatory support (high-flow nasal cannula or continuous positive airway pressure or non-invasive ventilation) or invasive mechanical ventilation; - patient is expected to be discharged from the hospital in the next 24 hours; - more than 14 days have elapsed since the commencement of hospital admission with respiratory illness; - known glucose-6-phosphate dehydrogenase (g6pd) deficiency; - known sickle cell anemia - pregnancy or breastfeeding; - known allergy to vitamin c; - known kidney stones within the past 1 year; - received any intravenous vitamin c during this hospitalization unless incorporated in parenteral nutrition; - expected death or withdrawal of life-sustaining treatments within 48 hours; - previously enrolled in this study; - previously enrolled in a trial for which co-enrolment is not allowed (co- enrolment to be determined case by case). the trial has broad eligibility criteria and includes all covid-19 patients admitted to the hospital (e.g. hospital ward or the intensive care unit) who are not receiving vasopressors.