Covid-long pathology affects a large number of patients, and represents a major medical, economic and societal challenge. To date, we have no objective criterion for a definitive diagnosis, nor any predictive tool for monitoring the evolution of Covid-long. Based on recruitment from the infectious diseases department of Nice University Hospital, the investigator's team wants to conduct an innovative pathophysiological study to better define the disease and identify specific biomarkers that could subsequently be used as a diagnostic tool for Covid-long. 120 participants will be initially included for the model learning phase: 60 controls in the CL- cohort and 60 patients in the CL+ cohort. Then 80 patients (40 CL+ and 40 Cl-) will be enrolled for the model validation phase.

FOR CL+ PATIENTS

Inclusion Criteria:

• Case definition in line with WHO Delphi process

Exclusion Criteria:

• History of chronic fatigue syndrome diagnosed before or after Covid.
• History of progressive psychiatric pathology.
• History of acute Covid requiring admission to intensive care and mechanical ventilation.
• No social security affiliation.

FOR CONTROL (CL-)

Inclusion Criteria:

• History of acute COVID-19, mild, moderate or severe (episode at least 3 months at the time of inclusion).
• Absence of persistent symptoms more than 3 months after first Covid symptoms (or mild not affecting daily activities).

Exclusion Criteria:

• History of progressive psychiatric pathology.
• History of acute Covid requiring admission to intensive care and mechanical ventilation.
• No social security affiliation.
• Pregnant or breast-feeding.

Not planned