Fig. 10.

SEIIR epidemiology model. Sensitivity with respect to the asymptomatic infectious period$C_{\mathrm{a}}$. Darkest curves correspond to a larger asymptomatic infectious period of $C_{\mathrm{a}}=2C_{\mathrm{s}}$, lightest curves to a smaller period $C_{\mathrm{a}}=0.5C_{\mathrm{s}}$. For a larger symptomatic fraction of ${\nu }_{\mathrm{s}}=0.8$, the outbreak dynamics are governed by the symptomatic population $I_{\mathrm{s}}$ and the recovered population $R$ is relatively insensitive to the asymptomatic infectious period $C_{\mathrm{a}}$ (left). For a smaller symptomatic fraction of ${\nu }_{\mathrm{s}}=0.2$, the outbreak dynamics are governed by the asymptomatic population $I_{\mathrm{a}}$ and the recovered population $R$ increases markedly with an increasing asymptomatic infectious period $C_{\mathrm{a}}$ (right). Latent period $A=2.5$ days, symptomatic infectious period $C_{\mathrm{s}}=6.5$ days, asymptomatic infectious period $C_{\mathrm{a}}=3.25$ days (left) and $C_{\mathrm{a}}=13$ days (right), and contact rate $\beta \left(t\right)={\beta }_0-\frac{1}{2}[1+tanh([t-t^{\ast }]∕T)][{\beta }_0-{\beta }_{\mathrm{t}}]$ with ${\beta }_0=0.65$ /days, ${\beta }_{\mathrm{t}}=0.10$ /days, $t^{\ast }=18.61$ days, and $T=10.82$ days.