The SARS-Cov2 viral pandemic is responsible for a new infectious disease called COVID-19 (CoronaVIrus Disease), is a major health problem. Respiratory complications occur in 15 to 40%, the most serious is acute respiratory distress syndrome (ARDS).

The management of COVID-19 is essentially symptomatic with respiratory oxygen supplementation in mild forms to invasive mechanical ventilation in the most severe forms.

Prone position (PP) reduced mortality in patients with ARDS in intensive care. Ding et al showed that PP and high flow oxygenation reduced the intubation in patients with moderate to severe ARDS.

The investigators hypothesize that the use of PP in spontaneously ventilation patients under oxygen standard could decrease incidence of intubation or non-invasive ventilation or death compared to conventional positioning management in medical departments.

This is a multicenter randomized controlled study. 400 patients with COVID-19 documentation and undergoing oxygen therapy will be randomly assigned, with a 1:1 ratio, to conventional positioning or repeated prone sessions.

The control group will have conventional positioning: semi-seated in bed or seated in a chair. The prone position is not allowed during the day (it is allowed at night if it is the natural sleeping position).

The intervention group will have:

• Two sessions minimum of prone position over the day. With a total objective of at least 2h30 of cumulated duration over the day. The objective is to spend as much time as possible in prone position if the patient tolerates it well.
• The maximum of prone position at night. Patients must be able to take position by themselves or with minimal assistance. The rails will be positioned in order to prevent falling out of bed. The patient will be free to choose his preferred prone position as long as the back is not compressed

Inclusion Criteria:

• Patients aged from 18 to 85 years old
• With COVID-19 documentation
• Undergoing oxygen therapy (nasal cannula, medium or high concentration mask or high flow nasal oxygen therapy)
• Able to move to PP by him/herself or with minimal assistance
• Written consent
• Hospitalized in COVID medical department for less than 72 hours

Exclusion Criteria:

• Pregnant (positive pregnancy test during screening) or breastfeeding women
• Patient on long-term oxygen therapy or Continuous Positive Airway Pressure (CPAP) or Non-Invasive Ventilation (NIV) at home
• Chronic Obstructive Pulmonary Disease (COPD) Patient stage 3 or 4
• Patient with known chronic diffuse interstitial lung disease
• Patient with neuromuscular pathology
• Contraindication to the PP (recent thoracic trauma, pneumothorax, orthopaedic fracture preventing mobilization, ...)
• Deep vein thrombosis of the lower limbs or pulmonary embolism with effective anticoagulation for less than 48 hours
• Hemodynamic instability (MAP < 65 mm Hg) persisting for more than 1 hour
• Respiratory rate greater than 40 cycles per minute
• Excessive use of accessory respiratory muscles (as judged by the clinician)
• Indication for curative NIV (acute pulmonary edema or acute hypercapnic respiratory failure)
• Intestinal Occlusive Syndrome
• Patient unable to protect upper airway
• Inability to understand French or to follow instructions for the prone position.
• Person under guardianship
• Protected Majors
• Not affiliated to French social security
• Decision not to forgo life sustaining therapy
• Patient discharged from an intensive care unit and has been treated by invasive or non-invasive mechanical ventilation at 2 pressure levels during the resuscitation stay.