Is dexamethasone a major Covid breakthrough?

Just how a big a deal is today’s announcement that the steroid anti-inflammatory drug Dexamethasone has been shown to be effective at lowering the death toll of Covid-19 patients? At first sight, this is a modest breakthrough. The drug was shown to reduce the death rate among patients on ventilators by a third and among those on oxygen by a fifth. Overall, it reduces 28-day mortality from the disease (the study doesn’t look at patients who may have died after that period) by 17 per cent. Notionally, had the effect of the drug been known at the beginning of the outbreak, it would have meant that we could have reduced