A Machine Learning Framework for Constructing Heterogeneous Contact Networks: Implications for Epidemic Modelling

2026-03-14

AI Summary

This study proposes a scalable framework for constructing individual contact networks that jointly accounts for age-structured mixing patterns and heterogeneity in contact frequency within populations. Leveraging empirical social contact survey data, the approach integrates machine learning with network modeling to generate transmission networks that preserve realistic contact structures, further incorporating contact duration as a weighting factor to better capture superspreading events. This work presents the first unified, scalable generative model that simultaneously embeds both age stratification and contact heterogeneity. Simulation results demonstrate that the interplay of these two factors substantially reduces epidemic size, enables more accurate reproduction of the observed secondary case distribution during the COVID-19 pandemic, and reveals a nonlinear suppression effect of lockdown measures on transmission opportunities.

Technology Category

• Search and Optimization: Mixed Discrete/Continuous Search
• Machine Learning: Deep Generative Models & Autoencoders
• Multiagent Systems: Agent-Based Simulation and Emergent Behavior

Application Category

• Social Networks and Social Media: Generative AI / large language models and their impact on social systems
• Graph Algorithms and Modeling for the Web: Foundation models and LLMs for Web-related graphs
• Security and Privacy: Large-scale security measurements

Abstract

Capturing the structured mixing within a population is key to the reliable projection of infectious disease dynamics and hence informed control. Both heterogeneity in the number of contacts and age-structured mixing have been repeatedly demonstrated as fundamental, yet are rarely combined. Networks provide a powerful and intuitive method to realise population structure, and simulate infection dynamics. However the explicit measurement of contact networks is not scalable to larger populations. Here, using data from social contact surveys, we develop a generalisable and robust algorithm utilizing machine learning to generate a surrogate population-scale network that preserves both age-structured mixing and heterogeneity of contacts. We simulate the spread of infection across different populations, considering how the epidemic size varies over basic reproduction number ($R_0$) scenarios - mirroring the process of determining public health impact from early epidemic growth. Our approach shows that both age structure and degree heterogeneity substantially reduce the epidemic size. We also demonstrate that these simulations more accurately capture the heterogeneity in secondary cases observed for COVID-19 when transmission is scaled by contact duration, dampening the effect of highly connected ``super-spreaders". By using survey data collected during 2020-2022, these network models also inform about the impacts of control and targeting of public health interventions: quantifying the non-linear reduction in transmission opportunities that occurred during lockdowns, and the ages and contact types most responsible for onward transmission. Our robust methodology therefore allows for the inclusion of the full wealth of data commonly collected by surveys but frequently overlooked to be incorporated into more realistic transmission models of infectious diseases.

Problem

• contact networks
• heterogeneity
• age-structured mixing
• epidemic modelling
• infectious disease transmission

Innovation

• machine learning
• heterogeneous contact networks
• age-structured mixing
• epidemic modelling
• contact duration