Modelling the circulating vaccine-derived polio infection in Cameroon

In Cameroon, the majority of poliomyelitis cases are attributed to the circulating vaccine-derived poliovirus (cVDPV). We present a reaction–diffusion model to assess the effect of infection due to cVDPV in Cameroon. We analyse the four-dose vaccination strategy currently implemented as the primary preventive measure in Cameroon. To effectively assess the impact of cVDPV infection, we consider two scenarios: one without cVDPV infection and the other with cVDPV. For the model without cVDPV, we show the existence, positivity, and uniqueness of solutions through the application of semigroup theory, Cauchy–Lipschitz theorem, and comparison principle. Next, we determine the disease-free equilibrium and the endemic equilibrium of the model, compute the reproduction number R 0 and demonstrate the global stability of equilibria using LaSalle’s Invariance Principle. In the second scenario, we show that the model with cVDPV lacks a disease-free equilibrium, and we study the existence of endemic equilibrium. By fitting our models to reported cases in Cameroon from 1980 to 2022, we estimate the model’s parameters. We perform a global sensitivity analysis with respect to R 0 , of the model without cVDPV to identify parameters with a relative influence on infection, and we investigate the effect of these parameters on model with cVDPV. Our outcomes reveal that the infection in population increases much more when the model includes cVDPV, and that an increase in the proportion of vaccinated newborns with a highly effective vaccine and implementing the four-dose vaccination strategy with high vaccine coverage significantly contribute to the prevention of cVDPV outbreaks in Cameroon.