Globally, the number of people affected by coronavirus disease 2019 (COVID-19) is rapidly increasing. In most (>80%), the illness is relatively mild and can be self-managed out of hospital. However, in about 20% the illness causes respiratory compromise severe enough to require hospital admission . Patients with severe and critical disease need full active treatment. This may include oxygen for hypoxaemia and ventilatory support, along with optimal management of complications, e.g. super-imposed bacterial infection, and any underlying co-morbidities, e.g. chronic obstructive pulmonary disease, congestive heart failure. To date, no antiviral agent has shown to be effective in treating the disease .