Fig. 1: Local outbreaks.
From: Endemic infectious states below the epidemic threshold and beyond herd immunity
Results of numerical generation of trajectories of the stochastic SIR model with external seeding in a single population using the Gillespie algorithm58,59. a (Example of a local outbreak of duration τ = 4.3 with parameters N = 105, \({{{{{{{{\mathcal{R}}}}}}}}}_{0}=0.8\), μ = 1/3.7 day−1 and h = 1.2. A shadowed area is placed where the disease is deactivated (I = 0). b Average duration 〈τ〉 of the first outbreak started from a single seed, I(0) = 1, S(0) = N, R(0) = 0 for different values of the external import (h) and of the basic reproductive number (\({{{{{{{{\mathcal{R}}}}}}}}}_{0}\)). In (c), similar to (b), but the outbreak starts from an initial condition beyond herd immunity, using the initial conditions of Eq. (8). Both in (b) and (c), the results have been averaged over 100 realizations and the errorbars signal the magnitude of the standard error.
