Fig. 2.

Value of X giving the minimum value of Eq. (12), as a function of Y and $\lambda$, based on numerical simulation of the cloSIR model. A clear transition from $X=0$ (yellow) to $X=1$ (blue) is seen, with no intermediary values. The solid black line corresponds to the theoretical closed-form solution from Eq. (13), while the dashed grey line corresponds to the rough approximation $Y>1-e^{-\lambda }$ past which it is best to not have any closures