Current inclusion criteria as of 13/05/2021: 1. Adult male or female individuals, age =18 years and =65 years 2. Patients giving written informed consent to participate in the study (ie GCS 15/15: conscious,Alert and oriented 3. COVID-19 documented by a positive RT-PCR test/Rapid Antigen Test 4. Hospitalised patients with severe COVID-19,requiring supplemental oxygen through non-re-Breath mask between 10 - 15L/min maintaining saturations between92-96% for up to 30 hours and between 94 - 98% for 1st six hours 5. Clinical/radiological evidence of interstitial pneumonia requiring admission(optional) _____ Previous inclusion criteria: 1. Aged between 18 and 65 years 2. COVID-19 infection documented by a positive RT-PCR test 3. Hospitalised with severe COVID-19 infection, characterized by fever (at the time of screening or when admitted) and requiring supplemental oxygen through non-rebreather mask between 10 and 15 l/ min 4. Clinical/radiological evidence of interstitial pneumonia requiring admission (optional) 5. Informed written consent given

Current inclusion criteria as of 13/05/2021: 1. Adult male or female individuals, age =18 years and =65 years 2. Patients giving written informed consent to participate in the study (ie GCS 15/15: conscious,Alert and oriented 3. COVID-19 documented by a positive RT-PCR test/Rapid Antigen Test 4. Hospitalised patients with severe COVID-19,requiring supplemental oxygen through non-re-Breath mask between 10 - 15L/min maintaining saturations between92-96% for up to 30 hours and between 94 - 98% for 1st six hours 5. Clinical/radiological evidence of interstitial pneumonia requiring admission(optional) _____ Previous inclusion criteria: 1. Aged between 18 and 65 years 2. COVID-19 infection documented by a positive RT-PCR test 3. Hospitalised with severe COVID-19 infection, characterized by fever (at the time of screening or when admitted) and requiring supplemental oxygen through non-rebreather mask between 10 and 15 l/ min 4. Clinical/radiological evidence of interstitial pneumonia requiring admission (optional) 5. Informed written consent given

1. Aged between 18 and 65 years 2. COVID-19 infection documented by a positive RT-PCR test 3. Hospitalised with severe COVID-19 infection, characterized by fever (at the time of screening or when admitted) and requiring supplemental oxygen through non-rebreather mask between 10 and 15 l/ min 4. Clinical/radiological evidence of interstitial pneumonia requiring admission (optional) 5. Informed written consent given

1. Aged between 18 and 65 years 2. COVID-19 infection documented by a positive RT-PCR test 3. Hospitalised with severe COVID-19 infection, characterized by fever (at the time of screening or when admitted) and requiring supplemental oxygen through non-rebreather mask between 10 and 15 l/ min 4. Clinical/radiological evidence of interstitial pneumonia requiring admission (optional) 5. Informed written consent given