Table 2.

Variables of the model.

Variable	Meaning
S	Susceptibles
N	Total population size
$E_i,i=1,\dots ,K_1$	Exposed individuals in different stages after the exposure to the disease
$I_i,i=1,\dots ,K_2$	Infectious individuals in different stages
$H_H$	Hospitalised individuals not requiring critical care
$H_C$	Hospitalised individuals requiring critical care
$C_C$	Individuals in critical care
$R_A$	Recovered asymptomatic individuals
$R_R$	Recovered individuals without hospitalisation
$R_H$	Recovered individuals after hospital (without critical care) admission
$R_C$	Recovered individuals after critical care
D	Those who died in critical care