Covid-19 is associated with the onset of anti-SARS-CoV-2 antibodies; in a majority of patients, neutralizing antibodies are detected. However, the long-term persistence of such protective antibodies is not known.~The investigators will explore adult patients with a proven Covid-19 (positive PCR) 6 and 12 months after the diagnosis to determine whether neutralizing antibodies are still detected.~The investigators will determine whether this persistance varies according to~the severity of the Covid-19 (3 groups: no oxyegn therapy; oxygen therapy of less than 3L/min; oxygen therapy of 3L/min or more)~a treatment by steroids during the covid-19. Immunocompromised patients will be excluded.
Covid-19 is associated with the onset of anti-SARS-CoV-2 antibodies; in a majority of patients, neutralizing antibodies are detected. However, the long-term persistence of such protective antibodies is not known.~The investigators will explore patients with a proven Covid-19 (positive PCR) 6 and 12 months after the diagnosis to determine whether neutralizing antibodies are still detected.~The investigators will determine whether this persistance varies according to~the severity of the Covid-19~a treatment by steroids during the covid-19. This will help to anticipate whether a second wave of infection is possible in a non-naive population.