Fig. 8: Transmission model and contact rates.
From: Model-based evaluation of school- and non-school-related measures to control the COVID-19 pandemic
a Model schematic. Black arrows show epidemiological transitions. Red arrows indicate the compartments contributing to the force of infection. Susceptible persons in age group k (Sk), where k = 1, …, n, become latently infected (Ek) via contact with infectious persons in m infectious stages (Ik,p, p = 1, …, m) at a rate βkλk, where λk is the force of infection, and βk is the reduction in susceptibility to infection of persons in age group k compared to persons in age group n. Exposed persons (Ek) become infectious (Ik,1) at rate α. Infectious persons progress through (m − 1) infectious stages at rate γm, after which they recover (Rk). From each stage, infectious persons are hospitalized at rate νk. Table 1 gives the summary of the model parameters. b–d Contact rates. b, c show contact rates in all locations before the pandemic and after the first lockdown (April 2020), respectively; d shows contact rates at schools before the pandemic. The color represents the average number of contacts per day a person in a given age group had with persons in another age group.
