Inclusion Criteria:  Age ≥18 years at the time of hospital admission. Confirmed SARS-CoV-2 infection by nucleic acid testing in the preceding 14 days of hospital admission. Admitted from the community (including continuing care facilities). Admitted to a hospital bed designated in the study. SpO2 ≤94% requiring supplemental oxygen or chest imaging findings compatible with COVID-19 pneumonia.  Exclusion Criteria:  The patient is enrolled in another clinical trial that involves antibacterial therapy. The patient's goals of care is anticipated to be designated "total compassionate care" or palliative care within 48 hours of admission. The patient's progression to death is anticipated to be imminent and inevitable within 48 hours of admission. The patient was attended by any member of the research team within 30 days of enrollment. The patient is transferred from another acute care center.