inclusion criteria: a potential participant must have met all the following criteria to be included in the study: 1. was hospitalized for laboratory-documented coronavirus disease 2019 (covid-19) (e.g., positive for severe acute respiratory syndrome coronavirus 2 \[sars-cov-2\] via nasopharyngeal swab real time polymerase chain reaction \[rt-pcr; or other commercial or public health assay\]). 2. was aged ≥18 years and ≤85 years. 3. had a resting oxygen saturation (sao2) of \<94% while breathing ambient air. 4. had a score of 3 or 4 on the national institute of allergy and infectious diseases (niaid) ordinal scale (required supplemental oxygen or non-invasive ventilation). 5. had provided informed consent to participate in the study (by participant or legally-acceptable representative).

inclusion criteria: a potential participant must have met all the following criteria to be included in the study: 1. was hospitalized for laboratory-documented coronavirus disease 2019 (covid-19) (e.g., positive for severe acute respiratory syndrome coronavirus 2 \[sars-cov-2\] via nasopharyngeal swab real time polymerase chain reaction \[rt-pcr; or other commercial or public health assay\]). 2. was aged ≥18 years and ≤85 years. 3. had a resting oxygen saturation (sao2) of \<94% while breathing ambient air. 4. had a score of 3 or 4 on the national institute of allergy and infectious diseases (niaid) ordinal scale (required supplemental oxygen or non-invasive ventilation). 5. had provided informed consent to participate in the study (by participant or legally-acceptable representative).

inclusion criteria: a potential participant must have met all the following criteria to be included in the study: was hospitalized for laboratory-documented coronavirus disease 2019 (covid-19) (e.g., positive for severe acute respiratory syndrome coronavirus 2 [sars-cov-2] via nasopharyngeal swab real time polymerase chain reaction [rt-pcr; or other commercial or public health assay]). was aged ≥18 years and ≤85 years. had a resting oxygen saturation (sao2) of <94% while breathing ambient air. had a score of 3 or 4 on the national institute of allergy and infectious diseases (niaid) ordinal scale (required supplemental oxygen or non-invasive ventilation). had provided informed consent to participate in the study (by participant or legally-acceptable representative).

inclusion criteria: a potential participant must have met all the following criteria to be included in the study: was hospitalized for laboratory-documented coronavirus disease 2019 (covid-19) (e.g., positive for severe acute respiratory syndrome coronavirus 2 [sars-cov-2] via nasopharyngeal swab real time polymerase chain reaction [rt-pcr; or other commercial or public health assay]). was aged ≥18 years and ≤85 years. had a resting oxygen saturation (sao2) of <94% while breathing ambient air. had a score of 3 or 4 on the national institute of allergy and infectious diseases (niaid) ordinal scale (required supplemental oxygen or non-invasive ventilation). had provided informed consent to participate in the study (by participant or legally-acceptable representative).

inclusion criteria: hospitalized for laboratory-documented covid-19 disease (e.g., positive for sars-cov-2 via nasopharyngeal swab rt-pcr [or other commercial or public health assay]). age ≥18 years and ≤85 years. resting oxygen saturation (sao2) of <94% while breathing ambient air. score of 3 or 4 on the niaid ordinal scale (requires supplemental oxygen or noninvasive ventilation). provide informed consent to participate in the study (by participant or legally-acceptable representative).

inclusion criteria: hospitalized for laboratory-documented covid-19 disease (e.g., positive for sars-cov-2 via nasopharyngeal swab rt-pcr [or other commercial or public health assay]). age ≥18 years and ≤85 years. resting oxygen saturation (sao2) of <94% while breathing ambient air. score of 3 or 4 on the niaid ordinal scale (requires supplemental oxygen or noninvasive ventilation). provide informed consent to participate in the study (by participant or legally-acceptable representative).

inclusion criteria: 1. hospitalized for laboratory-documented covid-19 disease (e.g., positive for sars-cov-2 via nasopharyngeal swab rt-pcr [or other commercial or public health assay]). 2. age ≥18 years and ≤85 years. 3. resting oxygen saturation (sao2) of <94% while breathing ambient air. 4. score of 3 or 4 on the niaid ordinal scale (requires supplemental oxygen or noninvasive ventilation). 5. provide informed consent to participate in the study (by participant or legally-acceptable representative).

inclusion criteria: 1. hospitalized for laboratory-documented covid-19 disease (e.g., positive for sars-cov-2 via nasopharyngeal swab rt-pcr [or other commercial or public health assay]). 2. age ≥18 years and ≤85 years. 3. resting oxygen saturation (sao2) of <94% while breathing ambient air. 4. score of 3 or 4 on the niaid ordinal scale (requires supplemental oxygen or noninvasive ventilation). 5. provide informed consent to participate in the study (by participant or legally-acceptable representative).