inclusion criteria: 1. male or female adults aged ≥18 years at the time of enrollment. 2. subjects with mild-to-moderate symptoms of respiratory illness caused by coronavirus 2019 infection as defined below: mild (uncomplicated) illness: * diagnosed with covid-19 by a standardized rt-pcr assay and * mild symptoms, such as fever, rhinorrhea, mild cough, sore throat, malaise, headache, muscle pain, or malaise, but with no shortness of breath and * no signs of a more serious lower airway disease and * rr\<20, hr \<90, oxygen saturation (pulse oximetry) \> 93% on room air moderate illness: * diagnosed with covid-19 by a standardized rt-pcr assay and * in addition to symptoms above, more significant lower respiratory symptoms, including shortness of breath (at rest or with exertion) or * signs of moderate pneumonia, including rr ≥ 20 but \<30, hr ≥ 90 but less than 125, oxygen saturation (pulse oximetry) \> 93% on room air and * if available, lung infiltrates based on x-ray or ct scan \< 50% present 3. clinically normal resting 12-lead ecg at screening visit or, if abnormal, considered not clinically significant by the principal investigator. 4. subject (or legally authorized representative) provides written informed consent prior to initiation of any study procedures. 5. understands and agrees to comply with planned study procedures.

inclusion criteria: 1. male or female adults aged ≥18 years at the time of enrollment. 2. subjects with mild-to-moderate symptoms of respiratory illness caused by coronavirus 2019 infection as defined below: mild (uncomplicated) illness: * diagnosed with covid-19 by a standardized rt-pcr assay and * mild symptoms, such as fever, rhinorrhea, mild cough, sore throat, malaise, headache, muscle pain, or malaise, but with no shortness of breath and * no signs of a more serious lower airway disease and * rr\<20, hr \<90, oxygen saturation (pulse oximetry) \> 93% on room air moderate illness: * diagnosed with covid-19 by a standardized rt-pcr assay and * in addition to symptoms above, more significant lower respiratory symptoms, including shortness of breath (at rest or with exertion) or * signs of moderate pneumonia, including rr ≥ 20 but \<30, hr ≥ 90 but less than 125, oxygen saturation (pulse oximetry) \> 93% on room air and * if available, lung infiltrates based on x-ray or ct scan \< 50% present 3. clinically normal resting 12-lead ecg at screening visit or, if abnormal, considered not clinically significant by the principal investigator. 4. subject (or legally authorized representative) provides written informed consent prior to initiation of any study procedures. 5. understands and agrees to comply with planned study procedures.

inclusion criteria: male or female adults aged ≥18 years at the time of enrollment. subjects with mild-to-moderate symptoms of respiratory illness caused by coronavirus 2019 infection as defined below: mild (uncomplicated) illness: diagnosed with covid-19 by a standardized rt-pcr assay and mild symptoms, such as fever, rhinorrhea, mild cough, sore throat, malaise, headache, muscle pain, or malaise, but with no shortness of breath and no signs of a more serious lower airway disease and rr<20, hr <90, oxygen saturation (pulse oximetry) > 93% on room air moderate illness: diagnosed with covid-19 by a standardized rt-pcr assay and in addition to symptoms above, more significant lower respiratory symptoms, including shortness of breath (at rest or with exertion) or signs of moderate pneumonia, including rr ≥ 20 but <30, hr ≥ 90 but less than 125, oxygen saturation (pulse oximetry) > 93% on room air and if available, lung infiltrates based on x-ray or ct scan < 50% present clinically normal resting 12-lead ecg at screening visit or, if abnormal, considered not clinically significant by the principal investigator. subject (or legally authorized representative) provides written informed consent prior to initiation of any study procedures. understands and agrees to comply with planned study procedures.

inclusion criteria: male or female adults aged ≥18 years at the time of enrollment. subjects with mild-to-moderate symptoms of respiratory illness caused by coronavirus 2019 infection as defined below: mild (uncomplicated) illness: diagnosed with covid-19 by a standardized rt-pcr assay and mild symptoms, such as fever, rhinorrhea, mild cough, sore throat, malaise, headache, muscle pain, or malaise, but with no shortness of breath and no signs of a more serious lower airway disease and rr<20, hr <90, oxygen saturation (pulse oximetry) > 93% on room air moderate illness: diagnosed with covid-19 by a standardized rt-pcr assay and in addition to symptoms above, more significant lower respiratory symptoms, including shortness of breath (at rest or with exertion) or signs of moderate pneumonia, including rr ≥ 20 but <30, hr ≥ 90 but less than 125, oxygen saturation (pulse oximetry) > 93% on room air and if available, lung infiltrates based on x-ray or ct scan < 50% present clinically normal resting 12-lead ecg at screening visit or, if abnormal, considered not clinically significant by the principal investigator. subject (or legally authorized representative) provides written informed consent prior to initiation of any study procedures. understands and agrees to comply with planned study procedures.

inclusion criteria: 1. male or female adults aged ≥18 years at the time of enrollment. 2. subjects with mild-to-moderate symptoms of respiratory illness caused by coronavirus 2019 infection as defined below: mild (uncomplicated) illness: - diagnosed with covid-19 by a standardized rt-pcr assay and - mild symptoms, such as fever, rhinorrhea, mild cough, sore throat, malaise, headache, muscle pain, or malaise, but with no shortness of breath and - no signs of a more serious lower airway disease and - rr<20, hr <90, oxygen saturation (pulse oximetry) > 93% on room air moderate illness: - diagnosed with covid-19 by a standardized rt-pcr assay and - in addition to symptoms above, more significant lower respiratory symptoms, including shortness of breath (at rest or with exertion) or - signs of moderate pneumonia, including rr ≥ 20 but <30, hr ≥ 90 but less than 125, oxygen saturation (pulse oximetry) > 93% on room air and - if available, lung infiltrates based on x-ray or ct scan < 50% present 3. clinically normal resting 12-lead ecg at screening visit or, if abnormal, considered not clinically significant by the principal investigator. 4. subject (or legally authorized representative) provides written informed consent prior to initiation of any study procedures. 5. understands and agrees to comply with planned study procedures.

inclusion criteria: 1. male or female adults aged ≥18 years at the time of enrollment. 2. subjects with mild-to-moderate symptoms of respiratory illness caused by coronavirus 2019 infection as defined below: mild (uncomplicated) illness: - diagnosed with covid-19 by a standardized rt-pcr assay and - mild symptoms, such as fever, rhinorrhea, mild cough, sore throat, malaise, headache, muscle pain, or malaise, but with no shortness of breath and - no signs of a more serious lower airway disease and - rr<20, hr <90, oxygen saturation (pulse oximetry) > 93% on room air moderate illness: - diagnosed with covid-19 by a standardized rt-pcr assay and - in addition to symptoms above, more significant lower respiratory symptoms, including shortness of breath (at rest or with exertion) or - signs of moderate pneumonia, including rr ≥ 20 but <30, hr ≥ 90 but less than 125, oxygen saturation (pulse oximetry) > 93% on room air and - if available, lung infiltrates based on x-ray or ct scan < 50% present 3. clinically normal resting 12-lead ecg at screening visit or, if abnormal, considered not clinically significant by the principal investigator. 4. subject (or legally authorized representative) provides written informed consent prior to initiation of any study procedures. 5. understands and agrees to comply with planned study procedures.