Why are Covid cases going down?

Imagine if the government had taken notice of the assorted scientists who, a couple of weeks ago, were imploring them to immediately enact ‘Plan B’ and reintroduce measures such as compulsory mask-wearing, working from home and limits on gatherings. The current dip in new Covid cases would be heralded as a sign of the success of the policy, and there would be calls for new lockdowns, or semi-lockdowns to control Covid infection numbers in the winter.

Something similar happened back in July when some scientific opinion was in favour of delaying the full reopening of the economy and society. At the time, professor Neil Ferguson warned that infection numbers would certainly hit 100,000 a day and could even reach 200,000. The government went ahead and reopened society anyway – and infection numbers began to fall almost immediately. It is perfectly reasonable to wonder whether the fall in infections which followed the lockdowns was also the result of government policy, or if it would have happened spontaneously.