Original Research ArticleThe HIV/TB coinfection severity in the presence of TB multi-drug resistant strains

•Novel fractional order model for HIV/TB coinfection with MDR-TB strains.•MDR-TB strains induce severity of the disease.•MDR-TB jeopardize 90-90-90 TB treatment target ad AIDS elimination.•The order of the fractional derivative, \alpha, brings additional information on the epidemics.•\alpha may be associated with individuals' specificities of the imune system.

We introduce a novel fractional-order model for the coinfection of HIV and tuberculosis (TB), in the presence of multi-drug resistant TB strains (MDR-TB) and treatment for both diseases. We compute the reproduction number of the HIV and TB submodels and of the full model and the local and global stabilities of the disease-free equilibria. Numerical simulations show the different dynamics of the model for variation of biologically relevant parameters, and for the order of the fractional derivative α ∈]0, 1]. The results obtained highlight the importance of treatment for HIV and TB and the role of the MDR-TB strains in the severity of the coinfection. Moreover, the order of the fractional derivative is a significant player in the epidemics theatre.