A quantitative analysis of COVID-19 transmission incorporating AstraZeneca immunization

Abstract

COVID-19 continues to pose a major global public health challenge due to its extensive transmission and associated mortality. In this work, a deterministic compartmental framework is developed to investigate the influence of the AstraZeneca vaccine on the spread of COVID-19. The disease-free equilibrium (DFE) of the proposed model is determined, and the effective reproduction number ( $R_e$ ) is computed using the next-generation matrix method. The theoretical analysis demonstrates that the DFE is both locally and globally asymptotically stable when ( $R_e < 1$ ), while it becomes unstable for ( $R_e > 1$ ). Furthermore, sensitivity analysis reveals that vaccination-related parameters play a dominant role in shaping ( $R_e$ ), with particular emphasis on the vaccination rate ( $\epsilon$ ) and vaccine efficacy ( $\gamma$ ). These findings indicate that enhanced vaccine coverage and improved effectiveness significantly suppress disease transmission, highlighting the importance of robust immunization strategies for mitigating COVID-19 outbreaks.