inclusion criteria (amendment 3, 15feb2021): 1. male and female hospitalized patients between 18 and 80 years of age at time of consent. 2. clinical and laboratory diagnosis of covid-19 infection. patients must be positive for the sars-cov-2 by real-time reverse transcriptase (rt)-pcr diagnostic panel or have an existing complication secondary to sars-cov-2 infection which was positive within 2 weeks of entry into the study. further, patients must have at least two of the following three symptoms: * fever (oral temperature ≥ 100.4 °f \[\> 38 °c\]) with or without chills * dyspnea or difficulty breathing (≤ 2 on mmrc dyspnea scale) * nonproductive cough * or other signs and symptoms of established complications to sars-cov-2 infection (e.g. coagulopathy, cardiomyopathy, acute kidney injury, and/or acute liver injury) within the limits of exclusion criteria 8 3. patients must present with moderate to severe illness as defined below: * moderate illness: patients who have evidence of lower respiratory disease by clinical assessment or imaging and an oxygen saturation (spo2) \> 93% on room air at sea level * severe illness: patients who have a respiratory frequency \> 30 breaths per minute (bpm), spo2 ≤ 93% on room air at sea level, ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (pao2/fio2) \< 300, or lung infiltrates \> 50%. 4. apache ii score \< 20 or establishment of survivability of the patient beyond 48 hours following randomization 5. therapies which have been shown to be beneficial and are included in standard covid-19 treatment guidelines (e.g. those of who or nih, or institutional guidelines) are permitted 6. sexually active women of child-bearing potential (wcbp) must be using a medically acceptable method of birth control throughout the study and for at least 1 day following the end of study, and have a negative urine pregnancy test at the screening visit. a wcbp is defined as a female who is biologically capable of becoming pregnant. a medically acceptable method of birth control includes intrauterine devices in place for at least 3 months, surgical sterilization, or the implant. in patients who are not sexually active, abstinence is an acceptable form of birth control and urine will be tested per protocol. women who are of nonchild-bearing potential, i.e., post-menopause, must have this condition captured in their medical history. pregnant women and nursing mothers are excluded from this study. 7. patient or lar is available and willing to give written informed consent, after being properly informed of the nature and risks of the study and prior to engaging in any study-related procedures.

inclusion criteria (amendment 3, 15feb2021): 1. male and female hospitalized patients between 18 and 80 years of age at time of consent. 2. clinical and laboratory diagnosis of covid-19 infection. patients must be positive for the sars-cov-2 by real-time reverse transcriptase (rt)-pcr diagnostic panel or have an existing complication secondary to sars-cov-2 infection which was positive within 2 weeks of entry into the study. further, patients must have at least two of the following three symptoms: * fever (oral temperature ≥ 100.4 °f \[\> 38 °c\]) with or without chills * dyspnea or difficulty breathing (≤ 2 on mmrc dyspnea scale) * nonproductive cough * or other signs and symptoms of established complications to sars-cov-2 infection (e.g. coagulopathy, cardiomyopathy, acute kidney injury, and/or acute liver injury) within the limits of exclusion criteria 8 3. patients must present with moderate to severe illness as defined below: * moderate illness: patients who have evidence of lower respiratory disease by clinical assessment or imaging and an oxygen saturation (spo2) \> 93% on room air at sea level * severe illness: patients who have a respiratory frequency \> 30 breaths per minute (bpm), spo2 ≤ 93% on room air at sea level, ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (pao2/fio2) \< 300, or lung infiltrates \> 50%. 4. apache ii score \< 20 or establishment of survivability of the patient beyond 48 hours following randomization 5. therapies which have been shown to be beneficial and are included in standard covid-19 treatment guidelines (e.g. those of who or nih, or institutional guidelines) are permitted 6. sexually active women of child-bearing potential (wcbp) must be using a medically acceptable method of birth control throughout the study and for at least 1 day following the end of study, and have a negative urine pregnancy test at the screening visit. a wcbp is defined as a female who is biologically capable of becoming pregnant. a medically acceptable method of birth control includes intrauterine devices in place for at least 3 months, surgical sterilization, or the implant. in patients who are not sexually active, abstinence is an acceptable form of birth control and urine will be tested per protocol. women who are of nonchild-bearing potential, i.e., post-menopause, must have this condition captured in their medical history. pregnant women and nursing mothers are excluded from this study. 7. patient or lar is available and willing to give written informed consent, after being properly informed of the nature and risks of the study and prior to engaging in any study-related procedures.

inclusion criteria (amendment 3, 15feb2021): male and female hospitalized patients between 18 and 80 years of age at time of consent. clinical and laboratory diagnosis of covid-19 infection. patients must be positive for the sars-cov-2 by real-time reverse transcriptase (rt)-pcr diagnostic panel or have an existing complication secondary to sars-cov-2 infection which was positive within 2 weeks of entry into the study. further, patients must have at least two of the following three symptoms: fever (oral temperature ≥ 100.4 °f [> 38 °c]) with or without chills dyspnea or difficulty breathing (≤ 2 on mmrc dyspnea scale) nonproductive cough or other signs and symptoms of established complications to sars-cov-2 infection (e.g. coagulopathy, cardiomyopathy, acute kidney injury, and/or acute liver injury) within the limits of exclusion criteria 8 patients must present with moderate to severe illness as defined below: moderate illness: patients who have evidence of lower respiratory disease by clinical assessment or imaging and an oxygen saturation (spo2) > 93% on room air at sea level severe illness: patients who have a respiratory frequency > 30 breaths per minute (bpm), spo2 ≤ 93% on room air at sea level, ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (pao2/fio2) < 300, or lung infiltrates > 50%. apache ii score < 20 or establishment of survivability of the patient beyond 48 hours following randomization therapies which have been shown to be beneficial and are included in standard covid-19 treatment guidelines (e.g. those of who or nih, or institutional guidelines) are permitted sexually active women of child-bearing potential (wcbp) must be using a medically acceptable method of birth control throughout the study and for at least 1 day following the end of study, and have a negative urine pregnancy test at the screening visit. a wcbp is defined as a female who is biologically capable of becoming pregnant. a medically acceptable method of birth control includes intrauterine devices in place for at least 3 months, surgical sterilization, or the implant. in patients who are not sexually active, abstinence is an acceptable form of birth control and urine will be tested per protocol. women who are of nonchild-bearing potential, i.e., post-menopause, must have this condition captured in their medical history. pregnant women and nursing mothers are excluded from this study. patient or lar is available and willing to give written informed consent, after being properly informed of the nature and risks of the study and prior to engaging in any study-related procedures.

inclusion criteria (amendment 3, 15feb2021): male and female hospitalized patients between 18 and 80 years of age at time of consent. clinical and laboratory diagnosis of covid-19 infection. patients must be positive for the sars-cov-2 by real-time reverse transcriptase (rt)-pcr diagnostic panel or have an existing complication secondary to sars-cov-2 infection which was positive within 2 weeks of entry into the study. further, patients must have at least two of the following three symptoms: fever (oral temperature ≥ 100.4 °f [> 38 °c]) with or without chills dyspnea or difficulty breathing (≤ 2 on mmrc dyspnea scale) nonproductive cough or other signs and symptoms of established complications to sars-cov-2 infection (e.g. coagulopathy, cardiomyopathy, acute kidney injury, and/or acute liver injury) within the limits of exclusion criteria 8 patients must present with moderate to severe illness as defined below: moderate illness: patients who have evidence of lower respiratory disease by clinical assessment or imaging and an oxygen saturation (spo2) > 93% on room air at sea level severe illness: patients who have a respiratory frequency > 30 breaths per minute (bpm), spo2 ≤ 93% on room air at sea level, ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (pao2/fio2) < 300, or lung infiltrates > 50%. apache ii score < 20 or establishment of survivability of the patient beyond 48 hours following randomization therapies which have been shown to be beneficial and are included in standard covid-19 treatment guidelines (e.g. those of who or nih, or institutional guidelines) are permitted sexually active women of child-bearing potential (wcbp) must be using a medically acceptable method of birth control throughout the study and for at least 1 day following the end of study, and have a negative urine pregnancy test at the screening visit. a wcbp is defined as a female who is biologically capable of becoming pregnant. a medically acceptable method of birth control includes intrauterine devices in place for at least 3 months, surgical sterilization, or the implant. in patients who are not sexually active, abstinence is an acceptable form of birth control and urine will be tested per protocol. women who are of nonchild-bearing potential, i.e., post-menopause, must have this condition captured in their medical history. pregnant women and nursing mothers are excluded from this study. patient or lar is available and willing to give written informed consent, after being properly informed of the nature and risks of the study and prior to engaging in any study-related procedures.

inclusion criteria: male and female hospitalized patients between 45 and 80 years of age at time of consent. clinical and laboratory diagnosis of covid-19 infection. patients must be positive for the sars-cov-2 by real-time reverse transcriptase (rt)-pcr diagnostic panel as well as two of the following three symptoms: fever (oral temperature ≥ 100.4 °f [> 38 °c]) with or without chills dyspnea or difficulty breathing (≤ 2 on mmrc dyspnea scale) nonproductive cough patients must present with moderate to severe illness as defined below: moderate illness: patients who have evidence of lower respiratory disease by clinical assessment or imaging and an oxygen saturation (spo2) > 93% on room air at sea level severe illness: patients who have a respiratory frequency > 30 breaths per minute (bpm), spo2 ≤ 93% on room air at sea level, ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (pao2/fio2) < 300, or lung infiltrates > 50%. apache ii score < 20 therapies which have been shown to be beneficial and are included in standard covid-19 treatment guidelines (e.g. those of who or nih) are permitted sexually active women of child-bearing potential (wcbp) must be using a medically acceptable method of birth control throughout the study and for at least 1 day following the end of study, and have a negative urine pregnancy test at the screening visit. a wcbp is defined as a female who is biologically capable of becoming pregnant. a medically acceptable method of birth control includes intrauterine devices in place for at least 3 months, surgical sterilization, or the implant. in patients who are not sexually active, abstinence is an acceptable form of birth control and urine will be tested per protocol. women who are of nonchild-bearing potential, i.e., post-menopause, must have this condition captured in their medical history. pregnant women and nursing mothers are excluded from this study. patient or lar is available and willing to give written informed consent, after being properly informed of the nature and risks of the study and prior to engaging in any study-related procedures.

inclusion criteria: male and female hospitalized patients between 45 and 80 years of age at time of consent. clinical and laboratory diagnosis of covid-19 infection. patients must be positive for the sars-cov-2 by real-time reverse transcriptase (rt)-pcr diagnostic panel as well as two of the following three symptoms: fever (oral temperature ≥ 100.4 °f [> 38 °c]) with or without chills dyspnea or difficulty breathing (≤ 2 on mmrc dyspnea scale) nonproductive cough patients must present with moderate to severe illness as defined below: moderate illness: patients who have evidence of lower respiratory disease by clinical assessment or imaging and an oxygen saturation (spo2) > 93% on room air at sea level severe illness: patients who have a respiratory frequency > 30 breaths per minute (bpm), spo2 ≤ 93% on room air at sea level, ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (pao2/fio2) < 300, or lung infiltrates > 50%. apache ii score < 20 therapies which have been shown to be beneficial and are included in standard covid-19 treatment guidelines (e.g. those of who or nih) are permitted sexually active women of child-bearing potential (wcbp) must be using a medically acceptable method of birth control throughout the study and for at least 1 day following the end of study, and have a negative urine pregnancy test at the screening visit. a wcbp is defined as a female who is biologically capable of becoming pregnant. a medically acceptable method of birth control includes intrauterine devices in place for at least 3 months, surgical sterilization, or the implant. in patients who are not sexually active, abstinence is an acceptable form of birth control and urine will be tested per protocol. women who are of nonchild-bearing potential, i.e., post-menopause, must have this condition captured in their medical history. pregnant women and nursing mothers are excluded from this study. patient or lar is available and willing to give written informed consent, after being properly informed of the nature and risks of the study and prior to engaging in any study-related procedures.

inclusion criteria: 1. male and female hospitalized patients between 45 and 80 years of age at time of consent. 2. clinical and laboratory diagnosis of covid-19 infection. patients must be positive for the sars-cov-2 by real-time reverse transcriptase (rt)-pcr diagnostic panel as well as two of the following three symptoms: - fever (oral temperature ≥ 100.4 °f [> 38 °c]) with or without chills - dyspnea or difficulty breathing (≤ 2 on mmrc dyspnea scale) - nonproductive cough 3. patients must present with moderate to severe illness as defined below: - moderate illness: patients who have evidence of lower respiratory disease by clinical assessment or imaging and an oxygen saturation (spo2) > 93% on room air at sea level - severe illness: patients who have a respiratory frequency > 30 breaths per minute (bpm), spo2 ≤ 93% on room air at sea level, ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (pao2/fio2) < 300, or lung infiltrates > 50%. 4. apache ii score < 20 5. therapies which have been shown to be beneficial and are included in standard covid-19 treatment guidelines (e.g. those of who or nih) are permitted 6. sexually active women of child-bearing potential (wcbp) must be using a medically acceptable method of birth control throughout the study and for at least 1 day following the end of study, and have a negative urine pregnancy test at the screening visit. a wcbp is defined as a female who is biologically capable of becoming pregnant. a medically acceptable method of birth control includes intrauterine devices in place for at least 3 months, surgical sterilization, or the implant. in patients who are not sexually active, abstinence is an acceptable form of birth control and urine will be tested per protocol. women who are of nonchild-bearing potential, i.e., post-menopause, must have this condition captured in their medical history. pregnant women and nursing mothers are excluded from this study. 7. patient or lar is available and willing to give written informed consent, after being properly informed of the nature and risks of the study and prior to engaging in any study-related procedures.

inclusion criteria: 1. male and female hospitalized patients between 45 and 80 years of age at time of consent. 2. clinical and laboratory diagnosis of covid-19 infection. patients must be positive for the sars-cov-2 by real-time reverse transcriptase (rt)-pcr diagnostic panel as well as two of the following three symptoms: - fever (oral temperature ≥ 100.4 °f [> 38 °c]) with or without chills - dyspnea or difficulty breathing (≤ 2 on mmrc dyspnea scale) - nonproductive cough 3. patients must present with moderate to severe illness as defined below: - moderate illness: patients who have evidence of lower respiratory disease by clinical assessment or imaging and an oxygen saturation (spo2) > 93% on room air at sea level - severe illness: patients who have a respiratory frequency > 30 breaths per minute (bpm), spo2 ≤ 93% on room air at sea level, ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (pao2/fio2) < 300, or lung infiltrates > 50%. 4. apache ii score < 20 5. therapies which have been shown to be beneficial and are included in standard covid-19 treatment guidelines (e.g. those of who or nih) are permitted 6. sexually active women of child-bearing potential (wcbp) must be using a medically acceptable method of birth control throughout the study and for at least 1 day following the end of study, and have a negative urine pregnancy test at the screening visit. a wcbp is defined as a female who is biologically capable of becoming pregnant. a medically acceptable method of birth control includes intrauterine devices in place for at least 3 months, surgical sterilization, or the implant. in patients who are not sexually active, abstinence is an acceptable form of birth control and urine will be tested per protocol. women who are of nonchild-bearing potential, i.e., post-menopause, must have this condition captured in their medical history. pregnant women and nursing mothers are excluded from this study. 7. patient or lar is available and willing to give written informed consent, after being properly informed of the nature and risks of the study and prior to engaging in any study-related procedures.

inclusion criteria: 1. male and female hospitalized patients between 45 and 80 years of age at time of consent. 2. clinical and laboratory diagnosis of covid-19 infection. patients must be positive for the sars-cov-2 by real-time reverse transcriptase (rt)-pcr diagnostic panel as well as two of the following three symptoms: - fever (oral temperature ≥ 100.4 °f [> 38 °c]) with or without chills - dyspnea or difficulty breathing (≤ 2 on mmrc dyspnea scale) - nonproductive cough 3. patients must present with moderate to severe illness as defined below: - moderate illness: patients who have evidence of lower respiratory disease by clinical assessment or imaging and an oxygen saturation (spo2) > 93% on room air at sea level - severe illness: patients who have a respiratory frequency > 30 breaths per minute (bpm), spo2 ≤ 93% on room air at sea level, ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (pao2/fio2) < 300, or lung infiltrates > 50%. 4. apache ii score < 20 5. use of hydroxychloroquine, chloroquine, azithromycin, remdesivir, or kaletra® (lopinavir/-ritonavir) is allowed if not part of another investigational study. 6. sexually active women of child-bearing potential (wcbp) must be using a medically acceptable method of birth control throughout the study and for at least 1 day following the end of study, and have a negative urine pregnancy test at the screening visit. a wcbp is defined as a female who is biologically capable of becoming pregnant. a medically acceptable method of birth control includes intrauterine devices in place for at least 3 months, surgical sterilization, or the implant. in patients who are not sexually active, abstinence is an acceptable form of birth control and urine will be tested per protocol. women who are of nonchild-bearing potential, i.e., post-menopause, must have this condition captured in their medical history. pregnant women and nursing mothers are excluded from this study. 7. patient or lar is available and willing to give written informed consent, after being properly informed of the nature and risks of the study and prior to engaging in any study-related procedures.

inclusion criteria: 1. male and female hospitalized patients between 45 and 80 years of age at time of consent. 2. clinical and laboratory diagnosis of covid-19 infection. patients must be positive for the sars-cov-2 by real-time reverse transcriptase (rt)-pcr diagnostic panel as well as two of the following three symptoms: - fever (oral temperature ≥ 100.4 °f [> 38 °c]) with or without chills - dyspnea or difficulty breathing (≤ 2 on mmrc dyspnea scale) - nonproductive cough 3. patients must present with moderate to severe illness as defined below: - moderate illness: patients who have evidence of lower respiratory disease by clinical assessment or imaging and an oxygen saturation (spo2) > 93% on room air at sea level - severe illness: patients who have a respiratory frequency > 30 breaths per minute (bpm), spo2 ≤ 93% on room air at sea level, ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (pao2/fio2) < 300, or lung infiltrates > 50%. 4. apache ii score < 20 5. use of hydroxychloroquine, chloroquine, azithromycin, remdesivir, or kaletra® (lopinavir/-ritonavir) is allowed if not part of another investigational study. 6. sexually active women of child-bearing potential (wcbp) must be using a medically acceptable method of birth control throughout the study and for at least 1 day following the end of study, and have a negative urine pregnancy test at the screening visit. a wcbp is defined as a female who is biologically capable of becoming pregnant. a medically acceptable method of birth control includes intrauterine devices in place for at least 3 months, surgical sterilization, or the implant. in patients who are not sexually active, abstinence is an acceptable form of birth control and urine will be tested per protocol. women who are of nonchild-bearing potential, i.e., post-menopause, must have this condition captured in their medical history. pregnant women and nursing mothers are excluded from this study. 7. patient or lar is available and willing to give written informed consent, after being properly informed of the nature and risks of the study and prior to engaging in any study-related procedures.