Inclusion Criteria:  Adult 18 years of age or older. Symptomatic and within 7 days of symptom onset.  High risk for severe disease (as defined by one or more of the following):  Age >50 Diabetes mellitus requiring therapy Hypertension on medication BMI >30 kg/m2 Cardiovascular disease Asthma requiring chronic controller medication Symptomatic respiratory disease Immunosuppressed patients (to maximum of 10mg prednisone daily +/- other immunosuppressive agents) Documented fever (>38C) One or more of the following symptoms: cough, shortness of breath (SOB), pleuritic chest pain and/or myalgias (to a maximum of 25% of enrollment) Discharged to home isolation. Willing and able to provide informed consent (including by substitute decision maker). Willing and able to follow-up by phone or videoconference. Female patients of childbearing potential and male patients with partners of childbearing potential must agree to use adequate methods of contraception during the study and through 90 days after the last dose of study medication. Female patients of childbearing potential are all those except patients who are surgically sterile, who have medically documented ovarian failure, or who are at least 1 year postmenopausal.  Exclusion Criteria:  Pregnancy (or positive urine pregnancy test) or lactating. More than 14 days following completion of SARS-CoV-2 vaccition series  The following pre-existing medical conditions:  Known cirrhosis with any history of decompensation (ascites, variceal bleeding or hepatic encephalopathy) Known chronic kidney disease with estimated creatinine clearance < 30 mL/minute or need for dialysis Uncontrolled severe psychiatric disorder - schizophrenia, bipolar disorder, depression with prior suicidality Uncontrolled seizures or seizure in the prior 1 month Any other underlying medical (cardiac, liver, renal, neurological, respiratory) or psychiatric condition that in the view of the investigator would preclude use of peginterferon lambda Known alcohol or drug dependence that in the opinion of the investigator would impair study participation. Known prior intolerance to interferon treatment. Enrolment in another clinical trial testing an antiviral agent or receipt of an antiviral agent for COVID-19 in the past 7 days. Use of investigational, off-label therapy for COVID-19, or unproven therapy for COVID-19.