Understanding Immunity to the Flu Vaccine in COVID-19 Patients

Inclusion Criteria: * Age 9 through 64 years * Diagnosed with COVID-19 at least 2 months prior enrollment * Patients with or without obesity, diabetes, chronic fatigue and/or long term COVID-19 symptoms * Patients without COVID-19 diagnosis for controls Exclusion Criteria: * Received the influenza vaccine less than 4 months ago * Pregnant or lactating * Patients with special risks attendant to venipuncture * Use of immunomodulatory medications that may impact vaccine immune response per clinician's judgment * Contraindication to the flu vaccine * Immunodeficiency or autoimmune disease that may impact vaccine immune responses per clinician's judgement