MATT RIDLEY: We know everything–and nothing–about Covid. The lockdowns were imposed in a state of ignorance. It now looks as if many of the early cases were caught in hospitals and doctors’ offices and nursing homes.

If Covid-19 is at least partly a ‘nosocomial’ (hospital-acquired) disease, then the pandemic might burn itself out quicker than expected. The death rate here [in the U.K.] peaked on 8 April, just two weeks after lockdown began, which is surprisingly early given that it is usually at least four weeks after infection that people die if they die. But it makes sense if this was the fading of the initial, hospital–acquired wave. If you look at the per capita numbers for different countries in Europe, they all show a dampening of the rate of growth earlier than you would expect from the lockdowns.

So if it wasn’t the lockdowns that slowed infection . . . .

It is possible that washing your hands, not shaking hands with others, not gathering in large crowds, and wearing a face mask in public, but no more than this, might have been enough, as Sweden seems to suggest. Forcibly shutting schools and shops and aggressively policing sunbathers in parks may have added little in terms of reducing the rate of spread.

But it did give politicians a chance to order everyone around, so there’s that.