Eligibility Criteria To be able to participate in the study, you must meet the following criteria: You are at least 18 years old.You have tested positive for COVID-19 (SARS-CoV-2, novel coronavirus). This requires evidence of a positive test result from a mouth or nasal swab.You are able to attend in-person study visits 3-4 times per year at our research center on the San Francisco General Hospital campus.