Fig. 3.

The effect of a change in ξ on the I_IC class. We have used $\beta =1/7,$$\eta =1/21,$ and $\alpha =1.13*{10}^{-8}$ as in Fig. 2, with a total population of $N=2*{10}^7,$ and ran simulations with $\xi =1/10$ (solid curve) and with $\xi =1/4$ (dashed curve). The substantial increase in ξ produces a reduction in the epidemic peak and a general slowing down of the dynamics, but both these effects are rather small.