EVOLUTIONARY DYNAMICS ANALYSIS OF VIRULENCE IN VIRAL INFECTIOUS DISEASE CO-INFECTION MODEL

In this paper, we study transmission dynamics of viral infectious diseases co-infection model and evolution dynamics of different strains virulence. First, original strain transmission model is developed by considering immune loss and reinfection mechanisms, and stability of equilibrium in the model is obtained. When basic reproduction number [Formula: see text], a mutant strain is introduced at endemic equilibrium of original strain transmission model, and two strains co-infection model is established. Second, using invasion analysis method, we obtain evolutionary singularity strategy properties through fitness function and evolutionary dynamics of average virulence and average transmission rate using population genetic method. Finally, numerical simulations are performed with COVID-19 data in the United States to obtain transmission rate as a function of virulence, contour plots of fitness function and time series diagrams of average virulence and average transmission rate, which provide theoretical guidance for controlling development of COVID-19 outbreaks.