COVID-19 Associated Lymphopenia Pathogenesis Study in Blood

Background: COVID-19 is an acute respiratory syndrome. One symptom of COVID-19 is a reduction in the number of cells called lymphocytes in the blood. Lymphocytes are a type of white blood cell that fights infections. With fewer lymphocytes, the body cannot effectively fight back against SARS CoV-2, the virus that causes COVID-19. Researchers want to better understand how SARS-CoV-2 affects these blood cells. This information may give them ideas for new treatments. Objective: To learn more about how SARS-CoV-2 affects lymphocytes, the immune, and the blood clotting system. Eligibility: Adults age 18 and older who either currently have COVID-19 or have recently recovered from it Design: Participants will give a blood sample. For this, a needle is used to collect blood from an arm vein. For participants who have a central line, blood will be collected through that instead. Participants medical records related to COVID-19 will be reviewed. Participants who have recovered from COVID-19 will be asked to undergo leukapheresis to collect white blood cells. For this, blood is taken from a needle placed in one arm. A machine separates out the white blood cells. The rest of the blood is returned to the participant through a needle placed in the other arm. This takes about 2-3 hours. Recovered participants may have material collected from inside the nostrils and/or rectum. This is done by gently rubbing the area with a sterile cotton swab. Recovered participants may have an echocardiogram to look at their heart. For this, a small probe is held against the chest to get pictures of the heart from different angles. This takes less than 30 minutes. Participation lasts 1-2 days on most cases and may be split in a few visits for recovered patients if leukapheresis and echocardiogram are done. ...

* INCLUSION CRITERIA: 1. Aged \>=18 years. 2. Diagnosis of COVID-19 via molecular assay or other commercial or public health assay. 3. Meets one of the following criteria for COVID-19: 1. Group A, mild clinical presentation: asymptomatic to oxygen requirements \4L NC to \50% FiO2 on high-flow oxygen devices, any other modality of non-invasive ventilation, or mechanical ventilation. 4. Group D, recovered: meets CDC criteria for discontinuation of transmission-based precautions and disposition of patients with COVID-19 in healthcare settings. Enrollment will occur at least 30 days after the above criteria were met. 4. Able to provide informed consent. EXCLUSION CRITERIA: Individuals meeting any of the following criteria will be excluded from study participation: 1. Documented history of hemoglobin from most recent blood draw \