Figure 1
From: Susceptible-Infected-Susceptible type COVID-19 spread with collective effects
Schematic representation of the extended SIS model with collective effects. \(I=I(t)\) is the proportion of population infected at time t, \(C=C(t)\) is the proportion of the population cooperating, g is the disease transmission rate, r is the disease recovery rate. The left diagram illustrates the flow between susceptible and infected and is identical to the standard SIS model, except that the constant transmission rate g in the SIS model has been replaced by a cooperation-dependent transmission rate \(g(1-C)\), and C is governed by the process in the right diagram. In particular, C decreases in a logistic type manner if the disease prevalence I is less than the collective cooperation threshold T, and C increases if I is larger than T.
