Note that in order for this kind of overshoot to happen, you basically have to have no social distancing whatsoever - not even voluntary changes to behaviour. I

Note that in order for this kind of overshoot to happen, you basically have to have no social distancing whatsoever - not even voluntary changes to behaviour. If there is any then it decreases the reproductive number R further, meaning that it drops below one and the epidemic peaks before enough people have been infected to provide herd immunity after everything returns to normal, and then herd immunity is only reached during the overshoot past the peak. (As I understand it, the UK government's original plans couldn't have lead to herd immunity in the first wave without this, since they were planning on substantial measures to reduce spread even under those plans.)