1. Patients age ≥ 18 years at screening 2. Hospitalisation with COVID-19 pneumonia AND - SARS-CoV2 infection (clinically suspected OR laboratory confirmed) AND - Radiological change consistent with COVID-19 disease 3. Grade 3 or 4 severity (WHO COVID-19 Ordinal Scale) 4. C-reactive protein (CRP) ≥50mg/L 5. Informed consent from patient or professional representative 6. No medical history that might, in the opinion of the responsible clinician, put the patient at significant risk if he/she were to participate in the trial 7. Agreement to abstain from sexual intercourse or use contraception that is >99% effective for all participants of childbearing potential for 42 days 8. For male participants, agreement to abstain from sperm donation for 42 days 9. Non-English speakers will be able to join the study. If patients are unable to understand verbal or written information in English - hospital translation services will be requested at the participating site for the participant where possible.

1. Patients age ≥ 18 years at screening 2. Hospitalisation with COVID-19 pneumonia AND - SARS-CoV2 infection (clinically suspected OR laboratory confirmed) AND - Radiological change consistent with COVID-19 disease 3. Grade 3 or 4 severity (WHO COVID-19 Ordinal Scale) 4. C-reactive protein (CRP) ≥50mg/L 5. Informed consent from patient or professional representative 6. No medical history that might, in the opinion of the responsible clinician, put the patient at significant risk if he/she were to participate in the trial 7. Agreement to abstain from sexual intercourse or use contraception that is >99% effective for all participants of childbearing potential for 42 days 8. For male participants, agreement to abstain from sperm donation for 42 days 9. Non-English speakers will be able to join the study. If patients are unable to understand verbal or written information in English - hospital translation services will be requested at the participating site for the participant where possible.