Comparison Between Prednisolone and Dexamethasone on Mortality in Patients on Oxygen Therapy, with CoViD-19

Inclusion Criteria: * Patient ≥ 18 years old * Patient with SARS-CoV-2 pneumopathy documented by nasopharyngeal or bronchoalveolar lavage fluid RT-PCR or any documented clinical symptoms support by CT scan * Patient with SpaO2 ≤ 94 % in room air (90% for patient with respiratory failure) and requiring an oxygen therapy * Negative pregnancy test for women of childbearing age * Informed and written informed consent (IC) obtained * Patients with affiliation to the social security system Exclusion Criteria: * Patient with corticosteroids as background treatment (≥ 10 mg equivalent) * Patient under supplemental oxygen \> 6 L/min * Immunocompromised patient (AIDS, bone marrow or solid organ transplants, etc.) * Patient who received a corticosteroid dose within 3 days for Covid-19 * Medical history of hypersensitivity to Prednisolone or Dexamethasone; or lactose / galactose (excipients with known effect) * Another active virus such hepatitis, herpes, varicella, shingles …. * Psychotic state not controlled by treatment