  This paper investigates the effects of vaccination on the dynamics of
infectious disease, which is spreading in a population concurrently with
awareness. The model considers contributions to the overall awareness from a
global information campaign, direct contacts between unaware and aware
individuals, and reported cases of infection. It is assumed that there is some
time delay between individuals becoming aware and modifying their behaviour.
Vaccination is administered to newborns, as well as to aware individuals, and
it is further assumed that vaccine-induced immunity may wane with time.
Feasibility and stability of the disease-free and endemic equilibria are
studied analytically, and conditions for the Hopf bifurcation of the endemic
steady state are found in terms of system parameters and the time delay.
Analytical results are supported by numerical continuation of the Hopf
bifurcation and numerical simulations of the model to illustrate different
types of dynamical behaviour.
