Moreover, based on the population migration, we assume that the input population and output population have constant numbers. Susceptible individuals S(t), exposed individuals E(t) and infectious individuals I(t) have their respective input individuals of p 1(t)A(t), p 2(t)A(t) and p 3(t)A(t), and the parameters p i(t), i  = 1, 2, 3 are the rates of susceptible individuals, exposed individuals, infectious individuals in the total input number of A(t) from other provinces. The output population are B 1, B 2 and B 3 for the susceptible individuals S(t), exposed individuals E(t), infectious individuals I(t). The COVID-19 disease transmission and population migration are demonstrated by Fig. 1 in details.
Figure 1 Flowchart of COVID-19 SEIRQ epidemic model.