Analysis of a Modified SEIRS Compartmental Model for COVID-19.

Mathematical representations of infectious diseases include compartment-based SEIR and SEIRS models. These models are represented using coupled differential equations that capture the flow of populations from one compartment to another. While these models have been used for several infectious diseases such as HIV/AIDS, tuberculosis, dengue fever, and COVID-19, the models do not generally incorporate compartments for vaccinated populations, asymptomatic infections, or the possibility of reinfection. This paper presents a modified Susceptible - Exposed - Infected - Recovered - Susceptible (SEIRS) compartment model for COVID-19 disease. We incorporate the compartments for exposed vaccinated and non-vaccinated populations, and those with symptomatic and asymptomatic infections. We represent this model with a set of coupled differential equations to show that this system has fixed points validated through attractor plots. Our results show that we have a fixed point that represents endemic equilibrium and that this fixed point is globally stable.