Fig. 2.

The effects of different levels of heterogeneity of individual susceptibility and course of disease. In (a), we plot $R\left(\infty \right)$ and $Var\left(\beta \right)$ (inset) as a function of $\langle \beta \rangle$, where the distribution of susceptibility is tuned as Poisson distribution (blue squares) and power-law distribution (red circles), individual course of disease satisfies Poisson distribution with $\langle {\gamma }^{-1}\rangle =6.5000$, $Var\left({\gamma }^{-1}\right)=18.7757$. In (b), we plot $R\left(\infty \right)$ and $Var\left({\gamma }^{-1}\right)$ (inset) as a function of $\langle {\gamma }^{-1}\rangle$, where the distribution of individual course of disease is tuned as Poisson distribution (blue squares) and power-law distribution (red circles), the susceptibility satisfies Poisson distribution with $\langle \beta \rangle =0.0556$, $Var\left(\beta \right)=0.0019$. Here, $m=n=30$, and individual degree satisfies power-law distribution with exponent $\mu =2.5$ and $M=100$.