Belief in conspiracy theories about COVID-19 vaccines among Brazilians: a national cross-sectional study

Emerson Lucas Silva Camargo, Caíque Jordan Nunes Ribeiro, Guilherme Reis de Santana Santos, Valdemar Silva Almeida, Herica Emilia Félix de Carvalho, Guilherme Schneider, Leticia Genova Vieira, André Luiz Silva Alvim, Fabiana Guerra Pimenta, Liliane Moretti Carneiro, Odinéa Maria Amorim Batista, Anderson Reis de Sousa, Álvaro Francisco Lopes de Sousa, Carla Aparecida Arena Ventura

Research output: Contribution to journalArticlepeer-review


Background: Vaccine hesitancy is a complex challenge that demands a comprehensive approach, one that not only acknowledges legitimate concerns within communities but also actively confronts misinformation. In this context, this study aimed to investigate the prevalence of belief in conspiracy theories about COVID-19 vaccines among Brazilians, seeking to understand the factors associated with this behavior. Method: Utilizing a national online survey conducted between May and August 2020, with a sample of 4247 participants, we conducted multivariate analysis to identify the independent determinants of this adherence, calculating adjusted prevalence ratios (APRs) and their 95% confidence intervals. Results: It was revealed that 27.7% of participants believed in at least one conspiracy theory. Factors associated with a higher level of adherence included agreement with at least one piece of COVID-19 misinformation on social media (APR: 3.65; 95% CI: 3.07–4.34), lack of difficulty accessing leisure activities during the pandemic (APR: 3.11; 95% CI: 1.85–5.24), age 50 years or older (APR: 1.70; 95% CI: 1.49–1.94), absence of difficulty accessing protective measures (APR: 1.47; 95% CI: 1.26–1.72), use of face masks (APR: 1.62; 95% CI: 1.33–1.97), non-use of at least one traditional media source for information (APR: 1.47; 95% CI: 1.26–1.72), female gender (APR: 1.41; 95% CI: 1.25–1.60), and age between 30 and 49 years (APR: 1.35; 95% CI: 1.19–1.52). Conclusions: Our findings highlight that it is crucial to recognize that vaccine hesitancy is not merely an isolated phenomenon but often rooted in a complex interplay of social, cultural, psychological, and political factors. There is a need for multifaceted strategies to combat vaccine hesitancy, effectively address conspiracy theories, and consider the various factors associated with their prevalence.

Original languageEnglish
Pages (from-to)518-530
Number of pages13
Issue number4
Publication statusPublished - Apr 2024


  • conspiracy theories
  • COVID-19
  • global health
  • health belief model
  • misinformation
  • vaccine hesitancy
  • vaccines


Dive into the research topics of 'Belief in conspiracy theories about COVID-19 vaccines among Brazilians: a national cross-sectional study'. Together they form a unique fingerprint.

Cite this