Dynamical evolution of social network polarization and its impact on the propagation of a virus
Ixandra Achitouv, David Chavalarias
TL;DR
This study analyzes how polarization around vaccination, inferred from Twitter networks during 2020–2022, shapes the diffusion of a virus. Using three real, bidirectional retweet networks labeled as pro- or anti-vaccine via clustering, the authors quantify evolving network properties (density, degree distribution, clustering, assortativity) and observe increasing polarization with cohesive anti-vaccine communities. They then couple these networks to an agent-based transmission model with vaccine effects, comparing polarized (vaccines allocated to pro-vaxx only) versus homogeneous vaccine distribution. Results show polarization accelerates and amplifies viral spread among unvaccinated individuals, with attack rates roughly 2.4× higher in early years, while vaccination within pro-vaxx clusters can screen transmission, underscoring the need to integrate opinion dynamics into epidemic forecasting and public health planning. The work provides a real-network, data-driven framework to study the coupled dynamics of social polarization and disease spread, with practical implications for vaccination strategies and misinformation mitigation.
Abstract
The COVID-19 pandemic that emerged in 2020 has highlighted the complex interplay between vaccine hesitancy and societal polarization. In this study, we analyse the dynamical polarization within a social network as well as the network properties before and after a vaccine was made available. Our results show that as the network evolves from a less structured state to one with more clustered communities. Then using an agent-based modeling approach, we simulate the propagation of a virus in a polarized society by assigning vaccines to pro-vaccine individuals and none to the anti-vaccine individuals. We compare this propagation to the case where the same number of vaccines is distributed homogeneously across the population. In polarized networks, we observe a significantly more widespread diffusion of the virus, highlighting the importance of considering polarization for epidemic forecasting.
