Here is some more observational evidence. If masks worked there would be a sudden interventional difference in the curves which didn't happen. There would not then have be a huge subsequent spike.
Pfizer's Data on its Vaccine. At p. 19 reports has killed 2 participants - along with 8 having severe adverse reactions and withdrawing from the trial. 4 people who supposedly took the “placebo” vaccine also died and another 5 with adverse effects.
https://fda.gov/media/144245/download…