Countering violent extremism: A mathematical model.

•Countering violent extremism modelled with an epidemic model.•Five compartments are considered: susceptible, vaccinated, recruiters, extremists and treatment.•The dynamics is determined by the basic reproduction number R0•If R0<1 the equilibrium with no terrorists is globally stable, and extremists and recruiters head for extinction.•Model is used to assess strategies to counter violent extremism.