Dynamics of a Fractional-Order Delayed Model of COVID-19 with Vaccination Efficacy

Fathalla A. Rihan, Udhayakumar Kandasamy, Hebatallah J. Alsakaji, Nicola Sottocornola

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


In this study, we provide a fractional-order mathematical model that considers the effect of vaccination on COVID-19 spread dynamics. The model accounts for the latent period of intervention strategies by incorporating a time delay (Formula presented.). A basic reproduction number, (Formula presented.), is determined for the model, and prerequisites for endemic equilibrium are discussed. The model’s endemic equilibrium point also exhibits local asymptotic stability (under certain conditions), and a Hopf bifurcation condition is established. Different scenarios of vaccination efficacy are simulated. As a result of the vaccination efforts, the number of deaths and those affected have decreased. COVID-19 may not be effectively controlled by vaccination alone. To control infections, several non-pharmacological interventions are necessary. Based on numerical simulations and fitting to real observations, the theoretical results are proven to be effective.

Original languageEnglish
Article number758
Issue number4
Publication statusPublished - Apr 2023


  • COVID-19
  • bifurcation
  • fractional-order
  • stability
  • time-delay
  • vaccination

ASJC Scopus subject areas

  • Immunology
  • Pharmacology
  • Drug Discovery
  • Infectious Diseases
  • Pharmacology (medical)


Dive into the research topics of 'Dynamics of a Fractional-Order Delayed Model of COVID-19 with Vaccination Efficacy'. Together they form a unique fingerprint.

Cite this