Inclusion Criteria:  Participant was diagnosed with COVID-19 and enrolled in a Phase III RO7496998 (AT-527) COVID-19 study  Exclusion Criteria:  Participation in an interventional study at the time of enrollment or plans to enroll in an interventional study during this study. Any serious medical condition or abnormality of clinical laboratory tests that, in the investigator's judgment, precludes the patient's safe participation in and completion of the study