A DELAYED DYNAMICAL MODEL FOR COVID-19 THERAPY WITH DEFECTIVE INTERFERING PARTICLES AND ARTIFICIAL ANTIBODIES

ABSTRACT

In this paper, we use delay differential equations to propose a mathematical model for COVID-19 therapy with both defective interfering particles and artificial antibodies. For this model, the basic reproduction number R-0 is given and its threshold properties are discussed. When R-0 < 1, the disease-free equilibrium E-0 is globally asymptotically stable. When R-0 > 1, E-0 becomes unstable and the infectious equilibrium without defective interfering particles E-1 comes into existence. There exists a positive constant R-1 such that E-1 is globally asymptotically stable when R-1 < 1 < R-0. Further, when R-1 > 1, E-1 loses its stability and infectious equilibrium with defective interfering particles E-2 occurs. There exists a constant R-2 such that E-2 is asymptotically stable without time delay if 1 < R-1 < R-0 < R-2 and it loses its stability via Hopf bifurcation as the time delay increases. Numerical simulation is also presented to demonstrate the applicability of the theoretical predictions.