[alkonaut]

> how much do face masks, school closures, or climate differences affect the virus spread

Shows how hard this is to actually find out. We have an enormous set of natural experiments and still each result is giving rise to more questions than answers. Are smokers better off? Does malaria drug X really help? How much do masks help? Do kids spread it a lot? Why are men more affected? We have no clue. We probably never will either, for many of the questions!