Population 1:  Inclusion Criteria:  Positive diagnostic test for COVID-19, influenza A or B virus, non COVID-19 coronavirus, parainfluenza virus, rhinovirus, adenovirus, or metapneumovirus Patient or legally authorized representative has provided verbal consent / verbal HIPAA (or parental permission form and assent form, as appropriate)  Exclusion Criteria:  None  Population 2:  Inclusion Criteria:  Positive diagnostic test for COVID-19 >14 days prior, OR potential to have been exposed to (and mounted antibodies against) COVID-19, OR positive diagnostic test for influenza A or B virus, non COVID-19 coronavirus, parainfluenza virus, rhinovirus, adenovirus, or metapneumovirus Patient or legally authorized representative has signed informed consent (or parental permission form and assent form, as appropriate)  Exclusion Criteria:  Patients with the following criteria:  Aged under 6 months old Anemia (Hgb <7) Platelet <80