You have misunderstood what R0 and R_effective mean. R0 certainly can, and often does, go below 1. The only difference between R0 and R_effective is that R0 ass

You have misunderstood what R0 and R_effective mean. R0 certainly can, and often does, go below 1. The only difference between R0 and R_effective is that R0 assumes everyone in the population is suaceptible to the virus.