‣ In order to be eligible to participate in this investigation, an individual must meet all of the following criteria:

‣ Cohort #1 (n=500):

• Evidence of personally signed and dated informed consent document indicating that the participant has been informed of all pertinent aspects of the study and was willing and able to consent to participation.

• Age ≥18 years old.

• Documented SARS-CoV-2 infection 6 or more months prior to screening, confirmed with acceptable documentation that includes (at minimum) their name, the date the test was taken (must be after January 2020), and details specifying that the positive test was for SARS-CoV-2 infection.

• Clinical evidence of Long COVID, as confirmed by the investigator's assessment:

• a. At least one symptom (listed below) that is new or worsened since the time of SARS-CoV-2 infection, not known to be attributable to another cause upon assessment by the study clinicians (MD, DO, NP, PA, RN, or equivalent).

• i. Systemic symptoms (e.g., fatigue, chills, post-exertional malaise), neurocognitive symptoms (e.g., trouble with memory/concentration (brain fog), headache, dysautonomia/postural orthostatic tachycardia syndrome, dizziness, unsteadiness, neuropathy, sleep disturbance), cardiopulmonary symptoms (e.g., chest pain, palpitations, shortness of breath, cough, fainting spells), musculoskeletal symptoms (e.g., muscle aches, joint pain), gastrointestinal symptoms (e.g., nausea, diarrhea). Although other symptoms (e.g., skin rash, hair loss, mental health symptoms, trouble with smell/taste, genitourinary symptoms) will be recorded and tracked, at least one core symptoms listed above must be present.

• b. Symptoms must be present for at least 6 months prior to screening. Symptoms that wax and wane must have been initially present at least 6 months prior to screening.

• c. Symptoms must be reported to have an impact on quality of life and/or everyday functioning and to be at least somewhat bothersome.

• d. Cognitive impairment present defined by having at least 20% positive items (answered subjectively worse or much worse) on the 41-item modified ECog questionnaire.

‣ Cohort #2 (n=50):

• Evidence of personally signed and dated informed consent document indicating that the participant has been informed of all pertinent aspects of the study and was willing and able to consent to participation.

• Age ≥18 years old.

• Clinical diagnosis of COVID infection between January 2020 and September 1, 2021 (i.e., before home tests were widely available).

• a. Clinical Criteria (Based on Council of State and Territorial Epidemiologists Standardized Surveillance Case Definition for COVID-19): i. At least two of the following symptoms: Fever (measured or subjective), chills, rigors, myalgia, headache, sore throat, new olfactory and taste disorder(s).

⁃ OR- ii. At least one of the following symptoms: Cough, shortness of breath, or difficulty breathing.

⁃ OR- iii. Severe respiratory illness with at least one of the following: clinical or radiographic evidence of pneumonia or Acute Respiratory Distress Syndrome (ARDS).

⁃ AND- iv. No alternate more likely diagnosis

• Clinical evidence of Long COVID, as confirmed by the clinician's assessment:

• a. At least one symptom (listed below) that is new or worsened since the time of SARS-CoV-2 infection, not known to be attributable to another cause upon assessment by the study clinicians (MD, DO, NP, PA, RN, or equivalent).

• i. Systemic symptoms (e.g., fatigue, chills, post-exertional malaise), neurocognitive symptoms (e.g., trouble with memory/concentration (brain fog), headache, dysautonomia/postural orthostatic tachycardia syndrome, dizziness, unsteadiness, neuropathy, sleep disturbance), cardiopulmonary symptoms (e.g., chest pain, palpitations, shortness of breath, cough, fainting spells), musculoskeletal symptoms (e.g., muscle aches, joint pain), gastrointestinal symptoms (e.g., nausea, diarrhea). Although other symptoms (e.g., skin rash, hair loss, mental health symptoms, trouble with smell/taste, genitourinary symptoms) will be recorded and tracked, at least one core symptoms listed above must be present.

• b. Symptoms must be present for at least 6 months prior to screening. Symptoms that wax and wane must have been initially present at least 6 months prior to screening.

• c. Symptoms must be reported to have an impact on quality of life and/or everyday functioning and to be at least somewhat bothersome.

• d. Cognitive impairment present defined by having at least 20% positive items (answered subjectively worse or much worse) on the 41-item modified ECog questionnaire.