title: Absence of epidemic threshold in scale-free networks with degree correlations.
abstract: Random scale-free networks have the peculiar property of being prone to the spreading of infections. Here we provide for the susceptible-infected-susceptible model an exact result showing that a scale-free degree distribution with diverging second moment is a sufficient condition to have null epidemic threshold in unstructured networks with either assortative or disassortative mixing. Degree correlations result therefore irrelevant for the epidemic spreading picture in these scale-free networks. The present result is related to the divergence of the average nearest neighbor's degree, enforced by the degree detailed balance condition.
authors.affiliation: Departament de Física Fonamental, Universitat de Barcelona, Avenida Diagonal 647, 08028 Barcelona, Spain.
authors.forename: Marián
authors.initials: M
authors.lastname: Boguñá
authors.forename: Romualdo
authors.initials: R
authors.lastname: Pastor-Satorras
authors.forename: Alessandro
authors.initials: A
authors.lastname: Vespignani
mesh_terms: D004812:Epidemiologic Methods; D008962:Models, Theoretical; D016571:Neural Networks, Computer; D012944:Social Support