Elisabetta Colosi, Bocconi University

Title: Discussion-based contact matrices as proxies for peer influence in coupled behaviour-epidemic models

Speaker: Elisabetta Colosi, Bocconi University

Chair: Fanny Bergström (JUNIPER Fellow), University of Oxford

Abstract:

Do the interactions that spread infections also shape the adoption of protective behaviour? In-person encounters provide opportunities for pathogen transmission, while conversations, whether in person, by phone or online, may provide opportunities for peer influence. Distinguishing these interactions raises questions about how we represent behavioural responses in epidemic models. Using data from the IMMUNE survey of 22,228 adults across six European countries, this talk compares age-stratified matrices of in-person and discussion contacts. We defined discussion contacts as the distinct individuals with whom respondents exchanged information about personal decisions or general topics during the week preceding the survey. We compare the two matrices in terms of age assortativity and contact rates across age groups. These matrices form the basis of a stochastic SIR model in which infection spreads through in-person contacts, while discussion contacts provide assumed pathways for behavioural change. We explore how feedback between infection dynamics and behavioural responses can generate multiple epidemic waves, and how age-specific interaction patterns shape behavioural trajectories. We also examine how these dynamics change under alternative representations of behavioural exposure, for example by using in-person contact patterns or excluding discussion contacts with children.

Please note the recording of this seminar, including Q&As with the audience, will be made public via YouTube.