Group-certain system away from ODEs
In order to address the potential impact of the implementation and easing of lockdown measures, we expand the model structure to group-specific compartments. Specifically, for given groups a = 1, …, A and any time t, set Sa(t) as the number of susceptible people in group a at time t, Ea(t) as the number of exposed people in group a at time t, and so on. The group-specific compartment model is characterised by the ODE system (3) for all groups a = 1, …, A, which is a direct extension of the ODE system of the basic compartment model for the special case A = 1. We define (4) as the effective contact rate between groups a and b, where w is the secondary attack rate, mabdominal is the specific mitigation effect by lockdown measures with regard to contacts between groups a and b, r is a general factor that accounts for compliance to distance, isolation and quarantine orders, hb is the proportion of infectious people in group b in need of hospitalisation and ?