Qualitative analysis of the SICR epidemic model with impulsive vaccinations

摘要

Control of epidemic infections is a very urgent issue today. To develop an appropriate strategy for vaccinations and effectively prevent the disease from arising and spreading, we proposed a modified Susceptible-Infected-Removed model with impulsive vaccinations. For the model without vaccinations, we proved global stability of one of the steady states depending on the basic reproduction number R_0. As typically in the epidemic models, the threshold value of R_0 is 1. If R_0 is greater than 1, then the positive steady state called endemic equilibrium exists and is globally stable, whereas for smaller values of R_0, it does not exist, and the semi-trivial steady state called disease-free equilibrium is globally stable. Using impulsive differential equation comparison theorem, we derived sufficient conditions under which the infectious disease described by the considered model disappears ultimately. The analytical results are illustrated by numerical simulations for Hepatitis B virus infection that confirm the theoretical possibility of the infection elimination because of the proper vaccinations policy.