Severity of a new variant

A sketch to explain how a new variant may appear milder even with no change in underlying virulence. This can occur because, when calculating the fraction of cases that are severe, the denominator now includes many re-infections that had previously been averted. A thread. 1/8 pic.twitter.com/XxrYHnb6XY

— Natalie E. Dean, PhD (@nataliexdean) December 9, 2021