The development and generalisation of vaccination led to a significant drop in the number of patients meeting the inclusion criteria.

Current data in the literature demonstrate that the immune response to CoV-2-SARS is much more complex than initially assumed. In fact, beyond the humoral response, including the existence of neutralizing CAs, the adaptive lymphocyte T-type immune response also appears to play an important role in controlling the infection and reducing the severity of the disease. At this stage, the analysis of this T response is still rudimentary and underdeveloped, but it seems crucial to be able to analyze it effectively in COVID-19 patients, which could help predict the evolution of the infection. It is also currently difficult to know the evolution of this response over time and especially after the resolution of the infection.

To this end, we will analyze the T lymphocyte response (ELISPOT and QUANTIFERON) based on the secretion of IFN (Th1) and IL-4 (Th2) by CoV-2-SARS specific T cells from COVID-19 patients. We will compare the T response to the quality of the systemic and mucosal humoral response. Finally, we will evaluate in parallel two new biomarkers of the severity of COVID-19: plasma calprotectin and the presence of antibodies to type 1 IFN antibodies.

Inclusion Criteria:

• Social security affiliation

• Signed informed consent

• Patients with COVID infection documented by PCR and/or antigenic testing

• Patients belonging to the following groups:

  • asymptomatic patients with PCR-positive PCR
  • patients with mild symptoms and PCR positive
  • seriously symptomatic patients with PCR positive
  • patients in resuscitation with positive PCR
  • Healthy individuals as controls

Exclusion Criteria:

• haemoglobin < 8g/dL
• Pregnancy, breastfeeding woman
• Patient vaccinated within 15 days prior to inclusion

Patients with COVID infection documented by PCR and/or antigenic testing will be included.