The purpose of this study is to understand why some people experience long term effects, such as shortness of breath and fatigue, after a severe COVID-19 infection

Each participant will be in the study for approximately 12 months and will be required to come to Mayo Clinic for 3 visits. These visits will take place approximately 2-3 months after confirmed COVID-19 diagnosis (visit 1), 6 months after diagnosis (visit 2), and 12 months after diagnosis (visit 3).

Comprehensive clinical evaluation and symptom characterization, quantitative lung CT image analysis and pulmonary function testing, and quality of life questionnaires will be obtained at each visit. Bronchoscopy with BAL (collected at visits 1 and 3 only) and blood samples (collected at all visits) will dissect the dynamic immunological and molecular signatures in the respiratory tract and in the circulation longitudinally. We will also perform highly sensitive viral reservoir or remnant assays to address the potential contribution of viral factors in regulating chronic lung conditions post-acute COVID-19.

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.

COVID-19 patient records from Mayo Clinic, Rochester MN and Mayo Clinic Health System sites will be reviewed for potential enrollment.