Canadian Adaptive Platform Trial of Treatments for COVID-19 in Community Settings (CanTreatCOVID)

Inclusion Criteria: Age 50 years and older or 18-49 with 1 or more chronic high-risk medical conditions, and/or immunosuppression: chronic respiratory disease (including COPD, cystic fibrosis and asthma requiring at least daily use of preventative and/or reliever medication); chronic heart or vascular disease; chronic kidney disease; chronic liver disease; chronic neurological disease (including dementia, stroke, epilepsy); severe and profound learning disability; Down's syndrome; diabetes (Type 1 or Type 2); immunosuppression: primary (e.g. inherited immune disorders resulting from genetic mutations) or secondary due to disease or treatment (e.g. sickle cell, HIV, cancer, chemotherapy); solid organ, bone marrow and stem cell transplant recipients; morbid obesity (BMI >35); severe mental illness; care home resident. Confirmed SARS-CoV-2 by nucleic acid testing or rapid antigen testing with proof of a positive test provided via a picture of the result Able to be enrolled and begin the study therapeutic within 5 days of onset of symptoms associated with SARS-CoV-2 infection Exclusion Criteria: Admitted to hospital or in an ED for more than 24 hours Previously randomized to CanTreatCOVID Currently participating in a clinical trial of a therapeutic agent for acute SARS-CoV-2 infection that is not/suspected not compatible with the study therapeutics Already taking a study therapeutic or contraindication to a study therapeutic Inability for participant or caregiver to provide informed consent Paxlovid Exclusion Criteria: History of clinically significant hypersensitivity to the active substances in Paxlovid™ (nirmatrelvir /ritonavir) or to any of its excipients. Patients with known rare hereditary problems of galactose intolerance, total lactase deficiency or glucose-galactose malabsorption. Patients with known current severe liver impairment (characterized by severe ascites, encephalopathy, jaundice, or prolonged INR. People with liver disease without any of these features are eligible). Patients with known moderate or severe renal disease (defined as CKD stage 3, 4 or 5 or current acute kidney injury or most recent eGFR in the past 6 months <60 ml/min). Currently taking Paxlovid™. Clinical requirement to continue taking a drug which is contraindicated or not recommended for administration with Paxlovid™ in the context of CanTreatCOVID or is taking a drug which in the opinion of the investigator would put the subject at unacceptable risk. Has a known or suspected pregnancy. Is breastfeeding. Is of childbearing potential and is not willing to use a highly effective contraceptive