Fig. 4.

Outbreak dynamics. Sensitivity with respect to the latent period $A$. Increasing the latent period increases the exposed population and decreases the infectious population. The susceptible and recovered populations converge to the same endemic equilibrium at $S_{\infty }=0.202$ and $R_{\infty }=0.798$, however, slower. The steepest susceptible, infectious, and recovery curves correspond to the SIR model without separate exposed population E with $A=0$ days with a maximum infectious population of $I_{max}=0.157$ after 86 days. Latent period $A=0,5,10,15,20,25$ days, infectious period $C=20$ days, basic reproduction number $R_0=C/B=2.0$, and initial exposed fraction $E_0=0.010$