Chronic Infections and Inflammation in ME/CFS: An Observational Study

Inclusion Criteria: * Willing and able to provide written informed consent * At least 18 years of age * Either: (1) a reported diagnosis of ME/CFS or (2) no history of ME/CFS or other infection-associated chronic conditions (healthy control) Exclusion Criteria: * Self reported or documented chronic anemia with hemoglobin \<9 g/dL * Known HIV, hepatitis B, or hepatitis C infection * Diagnosis of an infection-associated chronic condition other than ME/CFS or Long COVID (e.g. chronic Lyme disease, post-Ebola syndrome, etc.) * Serious medical or psychiatric illness that, in the opinion of the site investigator, would interfere with the ability to adhere to study requirements or to give informed consent * Active drug or alcohol use or dependence that, in the opinion of the PI, would interfere with adherence to study requirements or to give informed consent