Seasonal dynamics and control of malaria: A non-autonomous model incorporating vaccination and drug resistance

Abstract

This study develops and analyzes a seasonally forced malaria transmission model that incorporates vaccination, treatment, and the emergence of drug-resistant parasite strains. Using the periodic next-generation approach, we derive the vaccination-adjusted basic reproduction number R_v and establish conditions for the stability of the disease-free periodic solution. When R_v < 1, we show that malaria cannot persist and the disease-free state is globally asymptotically stable. Conversely, for R_v > 1, the infection is uniformly persistent and the system admits at least one positive T-periodic solution. A reduced autonomous version of the model reveals biologically interpretable thresholds for the dominance of either sensitive or resistant strains as well as coexistence scenarios. The model is calibrated using monthly malaria case data from Nigeria (2018–2024). The estimated reproduction number remains consistently above unity, indicating that malaria transmission is sustained under current intervention levels. Numerical simulations confirm these analytical results and illustrate the influence of vaccination coverage and drug resistance on long-term disease dynamics. Our findings highlight the need for strengthened intervention strategies to reduce R_v below one and interrupt sustained transmission.