* has at least one underlying medical condition associated with an increased risk of developing severe illness from covid-19 * history of or need for hospitalization for the medical treatment of covid-19 * prior diagnosis of sars-cov-2 infection (reinfection) * known medical history of liver disease * receiving dialysis or have known renal impairment * known human immunodeficiency virus (hiv) infection with viral load \> 400 copies/ml or taking prohibited medications for hiv treatment * suspected or confirmed concurrent active systemic infection other than covid-19 * current or expected use of any medications or substances that are highly dependent on cytochrome p450 3a4 (cyp3a4) for clearance or are strong inducers of cyp3a4 * has received or is expected to receive monoclonal antibody treatment or convalescent covid-19 plasma * has received any sars-cov-2 vaccine within 12 months of screening * participating in another interventional clinical study with an investigational compound or device, including those for covid-19 * known prior participation in this trial or other trial involving pf-07321332 * oxygen saturation of \< 92% on room air * females who are pregnant or breastfeeding

* has at least one underlying medical condition associated with an increased risk of developing severe illness from covid-19 * history of or need for hospitalization for the medical treatment of covid-19 * prior diagnosis of sars-cov-2 infection (reinfection) * known medical history of liver disease * receiving dialysis or have known renal impairment * known human immunodeficiency virus (hiv) infection with viral load \> 400 copies/ml or taking prohibited medications for hiv treatment * suspected or confirmed concurrent active systemic infection other than covid-19 * current or expected use of any medications or substances that are highly dependent on cytochrome p450 3a4 (cyp3a4) for clearance or are strong inducers of cyp3a4 * has received or is expected to receive monoclonal antibody treatment or convalescent covid-19 plasma * has received any sars-cov-2 vaccine within 12 months of screening * participating in another interventional clinical study with an investigational compound or device, including those for covid-19 * known prior participation in this trial or other trial involving pf-07321332 * oxygen saturation of \< 92% on room air * females who are pregnant or breastfeeding

has at least one underlying medical condition associated with an increased risk of developing severe illness from covid-19 history of or need for hospitalization for the medical treatment of covid-19 prior diagnosis of sars-cov-2 infection (reinfection) known medical history of liver disease receiving dialysis or have known renal impairment known human immunodeficiency virus (hiv) infection with viral load > 400 copies/ml or taking prohibited medications for hiv treatment suspected or confirmed concurrent active systemic infection other than covid-19 current or expected use of any medications or substances that are highly dependent on cytochrome p450 3a4 (cyp3a4) for clearance or are strong inducers of cyp3a4 has received or is expected to receive monoclonal antibody treatment or convalescent covid-19 plasma has received any sars-cov-2 vaccine within 12 months of screening participating in another interventional clinical study with an investigational compound or device, including those for covid-19 known prior participation in this trial or other trial involving pf-07321332 oxygen saturation of < 92% on room air females who are pregnant or breastfeeding

has at least one underlying medical condition associated with an increased risk of developing severe illness from covid-19 history of or need for hospitalization for the medical treatment of covid-19 prior diagnosis of sars-cov-2 infection (reinfection) known medical history of liver disease receiving dialysis or have known renal impairment known human immunodeficiency virus (hiv) infection with viral load > 400 copies/ml or taking prohibited medications for hiv treatment suspected or confirmed concurrent active systemic infection other than covid-19 current or expected use of any medications or substances that are highly dependent on cytochrome p450 3a4 (cyp3a4) for clearance or are strong inducers of cyp3a4 has received or is expected to receive monoclonal antibody treatment or convalescent covid-19 plasma has received any sars-cov-2 vaccine within 12 months of screening participating in another interventional clinical study with an investigational compound or device, including those for covid-19 known prior participation in this trial or other trial involving pf-07321332 oxygen saturation of < 92% on room air females who are pregnant or breastfeeding

- has received or is expected to receive any covid-19 vaccine, except for participants with an underlying medical condition associated with an increased risk of developing severe illness from covid-19. participants with these conditions who are fully vaccinated are considered to be at lower risk of developing severe disease and are therefore considered eligible. - history of or need for hospitalization for the medical treatment of covid-19. - prior diagnosis of sars-cov-2 infection (reinfection) - known medical history of liver disease - receiving dialysis or have known renal impairment - known human immunodeficiency virus (hiv) infection with viral load > 400 copies/ml or taking prohibited medications for hiv treatment - suspected or confirmed concurrent active systemic infection other than covid-19 - current or expected use of any medications or substances that are highly dependent on cytochrome p450 3a4 (cyp3a4) for clearance or are strong inducers of cyp3a4 - has received or is expected to receive monoclonal antibody treatment or convalescent covid-19 plasma - is expected to receive a sars-cov-2 vaccine between screening and the study day 34 visit - participating in another interventional clinical study with an investigational compound or device, including those for covid-19 - known prior participation in this trial or other trial involving pf-07321332 - oxygen saturation of < 92% on room air - females who are pregnant or breastfeeding

- has received or is expected to receive any covid-19 vaccine, except for participants with an underlying medical condition associated with an increased risk of developing severe illness from covid-19. participants with these conditions who are fully vaccinated are considered to be at lower risk of developing severe disease and are therefore considered eligible. - history of or need for hospitalization for the medical treatment of covid-19. - prior diagnosis of sars-cov-2 infection (reinfection) - known medical history of liver disease - receiving dialysis or have known renal impairment - known human immunodeficiency virus (hiv) infection with viral load > 400 copies/ml or taking prohibited medications for hiv treatment - suspected or confirmed concurrent active systemic infection other than covid-19 - current or expected use of any medications or substances that are highly dependent on cytochrome p450 3a4 (cyp3a4) for clearance or are strong inducers of cyp3a4 - has received or is expected to receive monoclonal antibody treatment or convalescent covid-19 plasma - is expected to receive a sars-cov-2 vaccine between screening and the study day 34 visit - participating in another interventional clinical study with an investigational compound or device, including those for covid-19 - known prior participation in this trial or other trial involving pf-07321332 - oxygen saturation of < 92% on room air - females who are pregnant or breastfeeding