Brussels

THE spread of the Covid-19 coronavirus across Europe and the United States has led to a sharp financial-market correction and prompted calls for active monetary and fiscal policy to prevent a recession. But a closer look suggests that such an approach might not help much at all.

The Covid-19 epidemic is marked by uncertainty. Technically, it does not represent a "black swan" event, because there have been other pandemics before. But it was, until a few months ago, unforeseeable, at least in specific terms. And it will have a long-lasting impact even if its precise evolution cannot be predicted today.