The writer is a senior fellow at Harvard Kennedy School

It is hard not to pity those who must produce a macroeconomic outlook for 2022. The paths of growth and inflation were already uncertain, and now there is the added unknown of the new coronavirus variant, Omicron. The chief executive of Moderna told the FT that existing vaccines are likely to be much less effective at tackling Omicron. The chief executive of BioNTech is more sanguine and expects fully vaccinated people will face only moderate illness. The World Health Organization says it’s possible the variant will be much more transmissible, but concurs that vaccines should protect against severe cases. And those are the experts.

With time, we’ll know the answers. But the central bankers who meet this month don’t have the luxury of time. The US Federal Reserve meets on December 14-15, the Bank of England and the European Central Bank on December 16. Will Omicron be a drag on demand that requires stimulus? Or a further boost to inflation that requires tighter monetary policy?