Figure 7.

Solution trajectories for the disease-free equilibrium. In this case, the assumed initial state value is (S(0),E(0),R(0))=(21000,250,18000) while varying the initial infected individuals between 1000 and 2000 with step size 200, the rate of vaccination is also assumed to be θ = 0.95, and the estimated parameter values are Λ = 9.289613942105396 × 10³, β = 0.007107 × 10³, ϵ = 0.001024 × 10³, μ = 0.0000002747 × 10³, γ = 1,  d = 0.0007795 × 10³.