The analysis of an epidemic model with time delay on scale-free networks

A new epidemic S I S model with time delay on scale-free networks is presented. We give the formula of the basic reproductive number for the model and prove that the disease dies out when the basic reproductive number is less than unity and the disease is uniformly persistent when the basic reproductive number is more than unity. The effects of various immunization schemes are studied. Numerical simulations are given to demonstrate the main results.