Modelling the effects of psychological fear and vaccination on the dynamics of typhoid fever

Abstract

Despite the great advancements in healthcare systems and sanitary improvements globally, sub-Saharan Africa including Kenya bears a significant burden of infectious diseases, among which typhoid fever continues to exert a notable toll. In this study, we developed a deterministic mathematical model to examine the interplay between human responses driven by the psychological factor of fear of infection, vaccination efforts, and the dynamics of human-to-human and environmental transmission of typhoid fever. The mathematical model was analyzed using theories of first order ordinary differential equations to establish the existence of equilibrium points and their conditions for local and global stability. The reproduction number, R₀, was established and distinct pathways for the transmission of infection were identified, shedding light on the crucial interactions among key population groups fueling the spread of typhoid fever disease. The model results suggests that, typhoid fever infection is heightened by both direct and indirect contact with infected individuals and contaminated environments. Additionally, lack or limited awareness contributes to decreased fear of infection and reluctance towards vaccination, further exacerbating the situation. Moreover, an increase in environmental transmission is observed due to elevated discharge rates from infected individuals. This study contributes valuable insights into the design of effective mitigation strategies aimed at combating typhoid fever in resource-limited settings.