A Study of Post COVID-19 Mechanisms for Chronic Lung Sequelae

Inclusion Criteria: For the Sequelae Group * Age ≥18 years at screening, PCR confirmed COVID19 illness (+PCR defines day 0 of illness), hospitalization for COVID-19, absence of pre-existing history of interstitial lung disease, or significant other lung disease. * Severity of illness will be categorized as moderate disease (supplemental oxygen need 1-8L at any time during hospitalization), severe disease (need for high flow oxygen delivery ≥8L at any time during hospitalization) and critical illness (need for ICU admission or mechanical ventilation). Control Recovery Group * Age ≥18 years at screening * PCR confirmed COVID-19 cases who had nonsymptomatic or mild acute infection that do not require hospitalization 7,48,49 * Absence of pre-existing history of interstitial lung disease, or significant other lung disease, absence of any ongoing respiratory and systemic symptoms. Exclusion Criteria: * Inability to provide informed consent, evidence of pre-existing interstitial lung disease or chronic lung disease; * Active cigarette smoking, vaping or other inhalation use. * Immunocompromised host status due to ongoing therapy with methotrexate, CellCept, azathioprine, rituximab, cyclophosphamide or other biologic agents; * \> 20 pack year smoking history. * History of chemotherapy or radiation therapy in the last two years; and pregnancy.