* persons with any clinical signs or symptoms suggestive of severe systemic illness with covid-19, including the following: 1. shortness of breath at rest 2. resting pulse ≥125 beats per minute 3. resting respiratory rate ≥30 breaths per minute 4. oxygen saturation ≤ 93% on room air at sea level * immunocompetent persons who have been fully vaccinated for sars-cov-2, defined as having received all expected vaccine doses for a 2-dose or single-dose series at least two weeks prior to onset of symptoms. * females of childbearing potential who are either pregnant or sexually active without the use of birth control. * subjects residing in the same household with another subject participating in the study. * treatment with any investigational drug or vaccine therapy within 30 days prior to screening. * receipt of monoclonal antibody therapy for covid-19 within the preceding 90 days. * receipt of any dose of ntz within seven days prior to screening. * known sensitivity to ntz or any of the excipients comprising the study medication. * subjects unable to swallow oral tablets or capsules. * subjects with known severe heart, lung, neurological or other systemic disease that the investigator believes could preclude safe participation. * subjects likely or expected to require hospitalization unrelated to covid-19 during the study period. * subjects taking medications considered to be major cyp2c8 substrates. * subjects who, in the judgment of the investigator, will be unlikely to comply with the requirements of this protocol.

* persons with any clinical signs or symptoms suggestive of severe systemic illness with covid-19, including the following: 1. shortness of breath at rest 2. resting pulse ≥125 beats per minute 3. resting respiratory rate ≥30 breaths per minute 4. oxygen saturation ≤ 93% on room air at sea level * immunocompetent persons who have been fully vaccinated for sars-cov-2, defined as having received all expected vaccine doses for a 2-dose or single-dose series at least two weeks prior to onset of symptoms. * females of childbearing potential who are either pregnant or sexually active without the use of birth control. * subjects residing in the same household with another subject participating in the study. * treatment with any investigational drug or vaccine therapy within 30 days prior to screening. * receipt of monoclonal antibody therapy for covid-19 within the preceding 90 days. * receipt of any dose of ntz within seven days prior to screening. * known sensitivity to ntz or any of the excipients comprising the study medication. * subjects unable to swallow oral tablets or capsules. * subjects with known severe heart, lung, neurological or other systemic disease that the investigator believes could preclude safe participation. * subjects likely or expected to require hospitalization unrelated to covid-19 during the study period. * subjects taking medications considered to be major cyp2c8 substrates. * subjects who, in the judgment of the investigator, will be unlikely to comply with the requirements of this protocol.

persons with any clinical signs or symptoms suggestive of severe systemic illness with covid-19, including the following: shortness of breath at rest resting pulse ≥125 beats per minute resting respiratory rate ≥30 breaths per minute oxygen saturation ≤ 93% on room air at sea level immunocompetent persons who have been fully vaccinated for sars-cov-2, defined as having received all expected vaccine doses for a 2-dose or single-dose series at least two weeks prior to onset of symptoms. females of childbearing potential who are either pregnant or sexually active without the use of birth control. subjects residing in the same household with another subject participating in the study. treatment with any investigational drug or vaccine therapy within 30 days prior to screening. receipt of monoclonal antibody therapy for covid-19 within the preceding 90 days. receipt of any dose of ntz within seven days prior to screening. known sensitivity to ntz or any of the excipients comprising the study medication. subjects unable to swallow oral tablets or capsules. subjects with known severe heart, lung, neurological or other systemic disease that the investigator believes could preclude safe participation. subjects likely or expected to require hospitalization unrelated to covid-19 during the study period. subjects taking medications considered to be major cyp2c8 substrates. subjects who, in the judgment of the investigator, will be unlikely to comply with the requirements of this protocol.

persons with any clinical signs or symptoms suggestive of severe systemic illness with covid-19, including the following: shortness of breath at rest resting pulse ≥125 beats per minute resting respiratory rate ≥30 breaths per minute oxygen saturation ≤ 93% on room air at sea level immunocompetent persons who have been fully vaccinated for sars-cov-2, defined as having received all expected vaccine doses for a 2-dose or single-dose series at least two weeks prior to onset of symptoms. females of childbearing potential who are either pregnant or sexually active without the use of birth control. subjects residing in the same household with another subject participating in the study. treatment with any investigational drug or vaccine therapy within 30 days prior to screening. receipt of monoclonal antibody therapy for covid-19 within the preceding 90 days. receipt of any dose of ntz within seven days prior to screening. known sensitivity to ntz or any of the excipients comprising the study medication. subjects unable to swallow oral tablets or capsules. subjects with known severe heart, lung, neurological or other systemic disease that the investigator believes could preclude safe participation. subjects likely or expected to require hospitalization unrelated to covid-19 during the study period. subjects taking medications considered to be major cyp2c8 substrates. subjects who, in the judgment of the investigator, will be unlikely to comply with the requirements of this protocol.