From Activism to Radicalization

The Evolution of Vaccine Disinformation in the Brazilian Social Media Ecosystem (2021–2025) 

Authors

  • Luana Chinazzo Federal University of Espírito Santo image/svg+xml , Internet and Data Science Laboratory (Labic/Ufes), Brasil
  • Anna Julia Teixeira de Oliveira Federal University of Espírito Santo image/svg+xml , Internet and Data Science Laboratory (Labic/Ufes), Brasil
  • Lucas Bragança Federal University of Espírito Santo image/svg+xml , Internet and Data Science Laboratory (Labic/Ufes), Brasil
  • Julia Firme Federal University of Espírito Santo image/svg+xml , Internet and Data Science Laboratory (Labic/Ufes), Brasil
  • Fabio Goveia Federal University of Espírito Santo image/svg+xml , Internet and Data Science Laboratory (Labic/Ufes), Brasil
  • Francis Sodré Federal University of Espírito Santo image/svg+xml , PPGSC (Ufes), Brasil

DOI:

https://doi.org/10.20318/recs.2026.9951

Keywords:

Disinformation, Vaccination, Social Media, Immunization Programs, Public Health

Abstract

Introduction: This article analyzes the evolution of the vaccination discourse in Brazil on the X platform, comparing the civic mobilization of 2021 with the radicalization and collapse of dialogue observed in 2025. Objectives: To analyse “Platform Effect” as the central variable explaining the discursive shift over time. Methodology: A comparative-longitudinal approach was used, employing semantic network analysis and co-occurrence graphs to map narratives and ecosystems across both periods. Results: Findings indicate that in 2021, platform architecture reduced organizing costs (Shirky), facilitating pro-vaccine activism. In contrast, 2025 shows the consolidation of radical niches where disinformation is quantifiably relevant, attributed to the reversal of affordances. The algorithmic prioritization of conflict and emotional intensity elevated contestation costs for scientific voices (Gillespie), creating a discursive vacuum. The anti-vaccine discourse became a “cultural war” against the PNI. Conclusion: The fight against disinformation is inseparable from the debate on the regulation and design of digital architecture, given the severe threat to public health and democratic integrity. 

 

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Published

2026-07-29
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Issue

Vol. 17 No. 2 (2026)

Section

Originals

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Copyright (c) 2026 Luana Chinazzo, Anna Julia Teixeira de Oliveira, Lucas Bragança, Julia Firme, Fabio Goveia, Francis Sodré

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How to Cite

Chinazzo, L., Teixeira de Oliveira, A. J., Bragança, L., Firme, J., Goveia, F., & Sodré, F. (2026). From Activism to Radicalization: The Evolution of Vaccine Disinformation in the Brazilian Social Media Ecosystem (2021–2025) . Revista Española De Comunicación En Salud, 17(2), 38-58. https://doi.org/10.20318/recs.2026.9951