From Figs. 1–4, we can see that the epidemic
peak, the time of the epidemic peak (tmax) and the
length of outburst are different. The individual population
for the higher contact rate and lower recovery rates (the longer duration for recovering) produce the
higher epidemic peak, tmax and length of the epidemic
outburst. As we see in Figs. 1–4, the peaks of the exposed
individuals for both front and back solutions are
higher than the peaks of the infectious ones because
some exposed individuals recover before they become
infectious. Furthermore, the distances from criticality
in these three waves are different because the product
of c and s is differen