Fig. 6.

Effects of vaccination as the only intervention strategy. Contour plots of the control reproduction number (${\mathcal{R}}_c$) of the model (2.1), as a function of vaccine coverage ($f_v$) and vaccine efficacy (${\epsilon }_v$), for the baseline scenarios in Table 3 and in the absence of mask usage in public for the US. Parameter values used are as given in Table 3 with ${\epsilon }_M=c_M=0$.