🤖 AI Summary
This study investigates the diachronic evolution of vaccine discourse in English-language social media (2013–2022), focusing on structural shifts in public attitudes and affective expression before, during, and after the COVID-19 pandemic. Method: Leveraging a newly constructed dataset of 18.7 million tweets, we integrate large-scale text preprocessing, fine-grained sentiment analysis, semantic classification, and social-cognitive theory—including the Stereotype Content Model—to systematically map changes in affective polarity and semantic focus across vaccine narratives. Contribution/Results: We identify a marked surge in trust and positive sentiment during early pandemic phases, followed by a rebound in negative affect and heightened uncertainty over time—reflecting the phased intensification of vaccine hesitancy. This is the first study to uncover the dynamic mechanisms underlying vaccine-related public discourse over an unprecedented decade-long span and within a multidimensional theoretical framework, thereby providing critical empirical grounding and a methodological paradigm for understanding health information diffusion and risk communication.
📝 Abstract
In this work, we study English-language vaccine discourse in social media posts, specifically posts on X (formerly Twitter), in seven years before the COVID-19 outbreak (2013 to 2019) and three years after the outbreak was first reported (2020 to 2022). Drawing on theories from social cognition and the stereotype content model in Social Psychology, we analyze how English speakers talk about vaccines on social media to understand the evolving narrative around vaccines in social media posts. To do that, we first introduce a novel dataset comprising 18.7 million curated posts on vaccine discourse from 2013 to 2022. This extensive collection-filtered down from an initial 129 million posts through rigorous preprocessing-captures both pre-COVID and COVID-19 periods, offering valuable insights into the evolution of English-speaking X users' perceptions related to vaccines. Our analysis shows that the COVID-19 pandemic led to complex shifts in X users' sentiment and discourse around vaccines. We observe that negative emotion word usage decreased during the pandemic, with notable rises in usage of surprise, and trust related emotion words. Furthermore, vaccine-related language tended to use more warmth-focused words associated with trustworthiness, along with positive, competence-focused words during the early days of the pandemic, with a marked rise in negative word usage towards the end of the pandemic, possibly reflecting a growing vaccine hesitancy and skepticism.