Some inexpensive and widely-available steroids can vastly improve the odds that very sick patients with COVID-19 can survive the illness.
This is according to a worldwide REMAP-CAP trial, which has also been trialled here in Ireland.
Professor Alistair Nichol is chair of critical care medicine in UCD.
He is also the director of the Irish Critical Care-Clinical Trials Network.
He told Ciara Kelly on Newstalk Breakfast the results are promising.
"This is really good news for patients who are unfortunate enough to get really unwell with COVID-19 and end up in intensive care units in Ireland.
"Steroids are a really inexpensive drug.
"The trial that we conducted that was published yesterday... actually showed that if we gave this inexpensive drug to patients when they enter the ICU and are very unwell, it can actually reduce the mortality rate from 40% to 32%.
"So that's a 20% reduction in mortality, and it can also reduce the need for the complex and expensive machines that people sometimes need to support organs when they're unwell".
"The steroid we actually used is called hydrocortisone; and a previous study that was published about two months ago in the UK - called 'Recovery' - used dexamethasone and it showed a benefit.
"I suppose what our study extends is actually it's not just one particular steroid works, it's actually the class of steroids that seem to have the protective effect.
"And that's an additional advantage - in a pandemic, you will hope that one drug, or one supply of drug, would not run low.
"What we're showing is actually a number of drugs which are similar all have the same protective effect".
But he added: "I would not recommend to anyone who is listening to this to go out and take steroids if they were unwell, or thought they had symptoms of COVID.
"This study that we did was very much confined to people who are critically unwell in the ICU.
"Steroids are a powerful drug that suppress the immune system, so we wouldn't recommend people to make this decision themselves".