simple ?

A few people responding to my chart of Covid’s falling IFR with "how do you know it fell because of vaccines, and not natural immunity?"

Here’s IFR overlaid on immunity levels via vax vs via infection. Spot which source of immunity rockets just as IFR collapses... 🧐 pic.twitter.com/vQ15qnPIeJ

— John Burn-Murdoch (@jburnmurdoch) February 15, 2022