UK experts say the low-dose steroid treatment is a major breakthrough in the fight against the deadly virus. It cut the risk of death by a third for patients on ventilators. For those on oxygen, it cut deaths by a fifth. The drug is part of the world’s largest trials testing existing treatments to see if they also work for coronavirus. Researchers estimate that if the drug had been available in the UK from the start of the coronavirus pandemic up to 5,000 lives could have been saved. Because it is cheap, it could also be of huge benefit in poorer countries struggling with high numbers of of Covid-19 patients. About 19 out of 20 patients with coronavirus recover without being admitted to hospital. Of those who are admitted to hospital, most also recover, but some may need oxygen or mechanical ventilation. These are the high-risk patients whom dexamethasone appears to help. The drug is already used to reduce inflammation in a range of other conditions, and it appears that it helps stop some of the damage that can happen when the body's immune system goes into overdrive as it tries to fight off coronavirus.