Fig. 3: The effects of spatially homogeneous control measures on long-term endemicity and short-term epidemicity of COVID-19 in Italy.
From: The epidemicity index of recurrent SARS-CoV-2 infections
a Plot of the relation between \({{\mathcal{R}}}_{{{c}}}\) (left axis, red), ec (right axis, blue), and the spatially uniform transmission rate reduction (ϵi = ϵ for all i’s). b Same as (a) for the effects of travel restrictions (ξij = ξ for all i’s and j’s). c Same as (a) for the effects of the isolation of infected individuals (\({\chi }_{i}^{X}=\chi\) for all i’s and X ∈ {E, P, I, A}). d Simultaneous deployment of controls leading to \({{\mathcal{R}}}_{{{c}}}=1\) (solid curves) or ec = 0 (dashed) for three values of ξ, the imposed travel restriction. The DFE is asymptotically unstable (\({{\mathcal{R}}}_{{{c}}}\,> \, 1\)) for parameter values below the solid curves and endowed with negative epidemicity (ec < 0) above the dashed curves. In all panels, wX = 1 (X ∈ {E, P, I, A}, see “Methods”). Colors at the bottom of a, c specify the ranges of endemicity/epidemicity conditions (red: \({{\mathcal{R}}}_{{{c}}}\, > \, 1\); gray: \({{\mathcal{R}}}_{{{c}}}\, <\, 1,{e}_{{{c}}}\,> \, 0\); blue: \({{\mathcal{R}}}_{{{c}}}\, <\, 1,{e}_{{{c}}}\, <\, 0\)). Parameters as in Table 2.
