Preliminary Evidence on Vaccine Misinformation Narratives on YouTube in Brazil: A Large-Scale Computational Analysis of Videos and User Comments
1
LABHDUFBA, Universidade Federal da Bahia, Salvador, Brazil
2
Instituto de Saúde Coletiva, Universidade Federal da Bahia, Salvador, Brazil
3
LABHDUFSC, Universidade Federal de Santa Catarina, Santa Catarina, Brazil
Popul. Med. 2026;8(Supplement Supplement 1):A3332
ABSTRACT
BACKGROUND:
Since 2020, Brazil has experienced a decline in vaccination coverage that cannot be explained solely by logistical limitations, but is associated with vaccine hesitancy and the circulation of misinformation in digital environments. In this context, YouTube constitutes a strategic space for the circulation of vaccine-related narratives. This study aims to analyze patterns in the dissemination of false, distorted, or inaccurate information about vaccines on the platform in Brazil.
METHODS:
We analyzed a corpus of YouTube videos collected in Brazil between 2020 and 2025, comprising approximately 600,000 videos retrieved through health-related queries. From this dataset, 34,322 vaccine-related videos were identified using Portuguese-language keywords applied to titles, descriptions, and transcripts, along with 518,831 associated user comments. Video metadata, textual content, and engagement indicators were analyzed using computational text analysis, complemented by qualitative content analysis of a stratified subsample.
RESULTS:
Preliminary results indicate that vaccine-related content represents a recurring subset of health content on Brazilian YouTube, with peaks corresponding to vaccination campaigns and public health controversies. Anti-vaccine narratives are advanced by diverse actors, including self-identified health professionals, political figures, and digital media channels, who mobilize different forms of epistemic authority. Dominant discourses include distrust of public institutions and the pharmaceutical industry, appeals to individual freedom, and conspiratorial framings. Affective strategies reinforce these arguments, while comment sections function as spaces of validation and contestation, contributing to the stabilization of vaccine skepticism over time.
CONCLUSIONS:
These findings suggest that YouTube operates as a structured ecosystem for the production, amplification, and social legitimation of vaccine misinformation. Understanding these dynamics is essential for developing platform-sensitive public health communication strategies aimed at countering misinformation and strengthening vaccine confidence.
Since 2020, Brazil has experienced a decline in vaccination coverage that cannot be explained solely by logistical limitations, but is associated with vaccine hesitancy and the circulation of misinformation in digital environments. In this context, YouTube constitutes a strategic space for the circulation of vaccine-related narratives. This study aims to analyze patterns in the dissemination of false, distorted, or inaccurate information about vaccines on the platform in Brazil.
METHODS:
We analyzed a corpus of YouTube videos collected in Brazil between 2020 and 2025, comprising approximately 600,000 videos retrieved through health-related queries. From this dataset, 34,322 vaccine-related videos were identified using Portuguese-language keywords applied to titles, descriptions, and transcripts, along with 518,831 associated user comments. Video metadata, textual content, and engagement indicators were analyzed using computational text analysis, complemented by qualitative content analysis of a stratified subsample.
RESULTS:
Preliminary results indicate that vaccine-related content represents a recurring subset of health content on Brazilian YouTube, with peaks corresponding to vaccination campaigns and public health controversies. Anti-vaccine narratives are advanced by diverse actors, including self-identified health professionals, political figures, and digital media channels, who mobilize different forms of epistemic authority. Dominant discourses include distrust of public institutions and the pharmaceutical industry, appeals to individual freedom, and conspiratorial framings. Affective strategies reinforce these arguments, while comment sections function as spaces of validation and contestation, contributing to the stabilization of vaccine skepticism over time.
CONCLUSIONS:
These findings suggest that YouTube operates as a structured ecosystem for the production, amplification, and social legitimation of vaccine misinformation. Understanding these dynamics is essential for developing platform-sensitive public health communication strategies aimed at countering misinformation and strengthening vaccine confidence.
| eISSN: | 2654-1459 |
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