1. Age over 18 years old 2. Visited within 48 hours 3. Respiratory sample was confirmed Covid-19 by RT-PCR 4. Evidence of pneumonia by chest imaging 5. Resting oxygen saturation between 90-94% 6. Voluntary consent

1. Age over 18 years old 2. Visited within 48 hours 3. Respiratory sample was confirmed Covid-19 by RT-PCR 4. Evidence of pneumonia by chest imaging 5. Resting oxygen saturation between 90-94% 6. Voluntary consent