COVID-19 is the lung disease caused by a virus called SARS-CoV-2, commonly referred to as the coronavirus. The coronavirus has different effects on different people. Many people who get the infection get mild or no symptoms at all and do not require hospital care. Of those who do come to hospital, some will be able to go home but some will need to be admitted for medical treatment including oxygen therapy or mechanical ventilation (where a machine is required to help with breathing). It has also become clear that some individuals remain symptomatic for many weeks or even months after the infection has cleared, this is referred to as Long Covid.