EUCTR2020‐001553‐48‐FR.

Methods	Trial design: open RCT Sample size: 304 Setting: inpatient Language: French Number of centres: 17 Type of intervention (treatment/prevention): treatment
Participants	Inclusion criteria Age ≥ 18 years old Hospitalisation for COVID‐19 infection confirmed by RT‐PCR or other virological method SpO2 ≤ 94% in ambient air measured twice at 5‐ to 15‐min intervals, or PaO2/FiO2 < 300 mmHg Abnormalities on the chest X‐ray or CT scan suggesting viral pneumonia Signature of a free and informed consent by the patient Exclusion criteria COVID‐19 infection with first symptoms > 9 days ago (depending on the patient’s questioning; the day of symptoms is defined as the first day with fever, cough, shortness of breath, and/or chills related to the COVID‐19 infection) Patients with primary or secondary immunodeficiency, including: HIV, chronic haematological disease, solid organ transplant, ongoing immunosuppressive treatment Long‐term corticosteroid therapy defined by taking > 10 mg/d (prednisone equivalent) Infection suspected or confirmed or with bacteria, fungal agents, or viruses (in addition to COVID‐19) Known contraindication to systemic corticosteroids Systolic blood pressure < 80 mmHg SpO2 < 90% under 5 L/min of oxygen in the mask at medium concentration, or higher oxygen requirements Patient on long‐term oxygen therapy Mechanical ventilation in progress Septic shock in progress Multi‐organ failure in progress Pregnant or breastfeeding woman (oral diagnosis) Lack of affiliation or beneficiary of a Social Security scheme Guardianship, curatorship or safeguard of justice
Interventions	Details of intervention Dose: prednisone 0.75 mg (concrete dosage/time frame missing) Route of administration: oral Treatment details of control group (e.g. dose, route of administration): standard care Concomitant therapy: no information
Outcomes	Primary study outcome Number of patients on day 7 of randomisation (i.e. on day 14 of symptoms ± 5 days) presenting a theoretical indication for transfer to ICU with a respiratory indication evaluated by an SpO2 < 90% stabilised at rest and under 5 L/min of oxygen at mask at medium concentration measured twice 5 to 15 min apart. The average value of the two measurements will be used.
Notes	Recruitment status: prematurely ended Prospective completion date: 7 months predicted Date last update was posted: unclear Sponsor/funding: Hospices Civils de Lyon