Fig. 6

Combined impact of age transition rates (\(d_{1}\)) and (\(d_{2}\)) on \({\mathscr {R}}_{0}\); (a) presents the 3D mesh plot, (b) shows the corresponding contour plot.

Combined impact of age transition rates (\(d_{1}\)) and (\(d_{2}\)) on \({\mathscr {R}}_{0}\); (a) presents the 3D mesh plot, (b) shows the corresponding contour plot.