Table 3 Factors contributing to the spread of conspiracy theories

Russell et al., 2011, USA [2]

Mistrust in government, socioeconomic status, racial/ethnic identity

Historical events (e.g., Tuskegee Study) amplify mistrust. Lower education and income increase susceptibility. Higher prevalence of conspiracy beliefs in minority populations.

High belief rates among Blacks (34.1%) and Hispanics (21.9%) vs. Whites (8%). Strong correlation with education and income levels. Beliefs were over three times more prevalent in minorities compared to Whites.

Ford et al., 2013, USA [1]

Historical discrimination, low trust in government

Reinforces mistrust in public health initiatives.

High levels of mistrust (72%) reported in study. Associations between mistrust and reduced testing behavior.

Hogg et al., 2017, South Africa [21]

Sociocultural context, HIV-related stigma and misinformation

Contributes to distrust in biomedical science and treatment. Amplifies fear and acceptance of non-evidence-based explanations.

AIDS denialism under Thabo Mbeki’s leadership delayed ART roll-out, fostering distrust. Lack of accurate knowledge among adolescents in Soweto.

Lahrach & Furnham, 2017, UK [24]

Religiousness, CAM use, perceived poor mental health

Higher religiousness and CAM use correlated with MCT belief. Poorer mental health increases vulnerability to conspiracy beliefs.

Correlations between these factors and MCT belief ranging from 0.13 to 0.49.

Sommariva et al., 2018, USA [14]

Popularity of alternative media sources, lack of evidence-based information

Alternative media outlets had the highest reach and share rate for rumors. Initial lack of verified content allowed rumors to dominate the conversation.

66% of popular news stories originated from alternative media. Rumors shared more widely than verified stories. WHO launched fact-checking efforts late in the process.

Featherstone & Zhang, 2020, USA [3]

Social media amplification, distrust in authorities

Frames that evoke distrust (e.g., government collusion) resonate emotionally and amplify misinformation. Social media bots and trolls manipulate narratives to promote anti-vaccine messages.

Bots and trolls on social media promoted anti-vaccine messages to foster skepticism. Misinformation content had higher engagement rates than verified health information.

Chen et al., 2020, Ecuador [6]

Social media dissemination of conspiracy theories

Rapid and widespread sharing of false information through social media platforms. Lack of fact-checking mechanisms allows misinformation to gain traction.

COVID-19 conspiracy beliefs mentioned 295,052 times in a single week on media platforms (cited in the study). High virality of misinformation compared to factual content.

Havey, 2020, USA [13]

Political ideology and polarization, social media echo chamber, populist rhetoric

Conservative users are more tolerant of misinformation. Facilitates consensus-seeking and amplifies misinformation. Promotes anti-science and conspiratorial narratives.

Conservatives dominate 5 of 6 misinformation topics, showing partisan spread of conspiracy theories. Twitter’s filter bubbles increase ideological reinforcement and misinformation spread. Conservatives reject public health guidelines, amplifying conspiracies through partisan media and political rhetoric.

Agley et al., 2021, USA [22]

Low trust in science, political orientation, perceived severity of COVID-19

Distrust in science and politicization of narratives amplify misinformation. Perceived severity of COVID-19 influences belief in conspiracy theories.

Statistical analysis shows a strong association between low trust in science and misinformation belief. Political orientation influences the likelihood of accepting conspiracy narratives.

Loomba et al., 2021, UK & USA [4]

Social media misinformation, sociopolitical influences, distrust of public health authorities

Misinformation spreads faster than factual content. Political polarization exacerbates distrust in public health authorities.

Misinformation exposure led to a measurable decline in vaccine intent. Sociopolitical factors like the 2020 US elections contributed to the spread of conspiracy beliefs.

Natoli & Marques, 2021, Australia [11]

Decreased trust in health authorities, feelings of powerlessness

Erodes confidence in medical recommendations. Amplifies skepticism towards pharmaceutical motives and public health guidelines.

Experimental studies showed reduced trust in health authorities following exposure to conspiracy theories. Feelings of powerlessness had varied influence on health-seeking behaviors.

Juanchich et al., 2021, UK [12]

Mistrust in government, reliance on social media, lower analytical thinking

Facilitates belief in misinformation and conspiracy theories. Lower analytical thinking increases vulnerability to misinformation.

Correlation between mistrust in government and conspiracy beliefs. Sharing of misinformation more frequent among conspiracy believers.

Dȩbski et al., 2022, Poland [7]

Belief in control of information, global conspiracies, personal well-being

Heightened information uncertainty, media contradictions, and anxiety about health and freedom. Increases reliance on conspiracy theories to explain uncertainties.

Correlation with belief in conspiracy theories (r = 0.768). Association with symptoms of anxiety and depression.

McCarthy et al., 2022, Australia [5]

Anomie, political ideology, perceived health threat

Increased perception of societal decline and reduced trust. Right-wing ideology associated with lower trust in government and higher conspiracy beliefs. Lower perceived health threat reduced need for vaccination.

Anomie was linked to greater vaccine hesitancy and acceptance of conspiracy beliefs. Bivariate correlations showed significant associations with vaccine hesitancy. Mediation models demonstrated how these factors influence hesitancy.

Jiang et al., 2022, Hong Kong [15]

Low political trust, viral spread of misinformation

Erodes trust in health advocacy and government, making individuals more susceptible. Higher influence of anti-vaccine messaging via social media platforms.

Distrust in Hong Kong government. Anti-vaccine messaging was highly influential through social media channels.

Swire-Thompson et al., 2023, USA [26]

Memory failures, disbelief in corrections, low depth of encoding

Memory failures lead to forgetting misinformation corrections, fostering belief regression. Shallow processing of corrective information limits long-term memory retention.

78% of participants who believed misinformation one month later misremembered corrections as affirmations. Evidence suggests that real-world corrections are processed more shallowly than experimental corrections.

Lin et al., 2023, multinational (66 countries) [16]

Social media proliferation, low trust in institutions, high HDI in wealthy nations

Social media amplified conspiracy theories. Distrust in government and science undermined compliance with public health measures.

Conspiracy endorsement was stronger in developed countries. Lower trust led to lower compliance with health interventions and public health guidelines.

Nefes et al., 2023, Spain [8]

Low trust in government health authorities, pharmaceutical companies, extreme right-wing ideology

Undermines belief in vaccine safety and adherence to public health guidelines. Fosters suspicion of vaccine development motives and misinformation acceptance. Promotes conspiratorial narratives against health policies and institutions aligned with opposing ideologies.

R-squared: 0.09 association with lower trust in health authorities correlating to conspiracy beliefs. R-squared: 0.24 significant negative association between trust in pharmaceutical companies and conspiracy beliefs. Participants identifying as extreme-right showed 0.35 SD greater conspiracy beliefs than centrists.

Walter et al., 2023, USA [25]

Politicization of science, use of scientific language by extremists, White nationalist ideology

Promotes distrust in scientific consensus, leveraging pre-existing partisan divides. Dresses conspiracy theories in scientific terms, making them appear credible. Connects conspiracy theories to racist and anti-Semitic narratives, spreading distrust in public health.

Conservative media and political figures like President Trump undermined health officials and science. Posts often discussed vaccine development and alternative medicine using pseudo-scientific language. Users described vaccines as tools for demographic control and labeled COVID-19 as a Jewish hoax.

Banas et al., 2024, USA [23]

Misinformation, emotional narratives, distrust in public health

Misinformation undermines decision-making. Emotional narratives reinforce beliefs and distrust amplifies skepticism toward public health.

References to anti-vaccination propaganda, particularly Andrew Wakefield’s fraudulent research and the documentary “Vaxxed.”

Kapoor et al., 2024, India [10]

Low socioeconomic status, right-leaning ideology, negative moral emotions

Creates a sense of powerlessness, endorses alternative narratives, and fosters mistrust in public health authorities.

Regression analysis highlighted predictors of conspiracy beliefs, including low socioeconomic status, right-leaning ideology, negative moral emotions, and mistrust in political institutions.

Lyons et al., 2024, USA [17]

False cancer beliefs, conspiracism, anti-expert sentiments, low digital and health literacy

False cancer beliefs, conspiracism, and anti-expert sentiments predispose individuals to endorse misinformation. Low digital and health literacy make it harder for individuals to evaluate the credibility of information.

False cancer beliefs strongly predicted perceived accuracy of inaccurate headlines and greater sharing intent for such misinformation. Strong correlation between low digital literacy and endorsement of inaccurate news headlines.

Carletto et al., 2024, USA [9]

Low education levels, medical mistrust, non-reliance on credible sources

Less ability to critically assess information, distrust in institutions increases conspiracy beliefs.

Lower education = 22% more likely to believe myths, higher mistrust = 72% more likely.

Kroke & Ruthig, 2024, USA & Canada [27]

Sociopolitical distrust, misinformation through social media, perceived lack of transparency

Undermines trust in health messages, promotes alternative narratives.

Strong correlation between endorsement of conspiracy theories and reduced vaccination.

Moran et al., 2024, USA [18]

Parasocial relationships, platform affordances, distrust in institutions, gendered narratives

Build trust through relatability and emotional connection; platform features like Instagram Stories amplify content.

Observations of influencers using personal anecdotes and religious narratives to gain trust and spread vaccine misinformation.