BBC news reports that a cheap and widely available drug, low-dose dexamethasone, has been proven effective at reducing Covid-19 death rates by as much as a third for the hardest-hit patients, those on ventilators.
The drug is part of the world's biggest trial testing existing treatments to see if they also work for coronavirus.
It cut the risk of death by a third for patients on ventilators. For those on oxygen, it cut deaths by a fifth.
Had the drug had been used to treat patients in the UK from the start of the pandemic, up to 5,000 lives could have been saved, researchers say.
And it could be of huge benefit in poorer countries with high numbers of Covid-19 patients.
The UK government has stockpiled 200,000 courses the drug and says the NHS will make dexamethasone available as treatment for patients on ventilators and oxygen.It's not a vaccine. It won't protect people from contracting the virus. It won't prevent infected people from infecting others. It will, where it's available, somewhat reduce death rates.