The propagation of model epidemics on a small-world network under the action
of immunization is studied. Although the connectivity in this kind of networks
is rather uniform, a vaccination strategy focused on the best connected
individuals yields a considerable improvement of disease control. The model
exhibits a transition from disease localization to propagation as the disorder
of the underlying network grows. As a consequence, for fixed disorder, a
threshold immunization level exists above which the disease remains localized.Comment: 10 pages, 4 figur