In one of the first studies to examine the roots of anti-vaccination attitudes, researchers have concluded that a belief in conspiracy theories is associated with a greater likelihood in an individual holding anti-vaccination views. Furthermore, it is ‘counterproductive’ to reduce an individual’s ‘conspiratorial thinking’, when aiming to create change.

The study, conducted by the University of Queensland, was instigated in light of increasing incidences of measles, mumps and pertussis in the U.S. for the first time in a century (WHO, 2017). To identify the ‘attitude roots’ of vaccine rejection, a survey was issued online and completed by 5,323 usable participants in 24 different countries. Conspiratorial beliefs, disgust sensitivity, reactance (the tendency for people to have a low tolerance for impingements on their freedoms), and individualistic/hierarchical worldviews, were the 4 attitudes assessed.

To measure conspiratorial beliefs, the survey used 4 conspiracies considered to have worldwide recognition: conspiracies surrounding the assassination of John F. Kennedy, the death of Princess Diana, the existence of a New World Order, and any government knowledge of the 9/11 terrorist attacks. Respondents were asked to rate their agreement to the possibility of a conspiracy. 

Disgust responses toward blood and needles were measured using the Disgust Emotion Scale (Olatunji et al; 1 for no disgust to 5 for extreme disgust or repugnance). Six hypothetical events (e.g. “receiving an anesthetic injection in the mouth”) were presented for rating. Reactance was measured using agreement (on a 1 to 5 scale) to a selection of statements from the Hong Psychological Reactance Scale (Hong & Page). And individualism was measured using the Cultural Cognition Worldview Scale (Kahan et al.)

Bivariate relationships were calculated by a series of meta-analyses using the metafor package (Viechtbauer, 2010).

The results showed that anti-vaccination attitudes were highest among participants with strong beliefs in conspiracies (correlation [r]=0.334, P<0.001). The next most consistent relationship with anti-vaccination was in reactance, the higher people rated on the reactance scale the more likely they were to hold anti-vaccination attitudes (r=0.235, P<0.001).

Stronger anti-vaccination attitudes were also evident in those with high levels of disgust toward blood/injections and those with individualistic worldviews, however these relationships were weaker in terms of effect size, than conspiratorial beliefs and reactance.

Examining their findings, the authors hypothesize that “The particularly strong role of conspiratorial beliefs helps contextualize why corrective information and myth-busting about vaccinations has tended to be either ineffective or counterproductive.”

“Trying to reduce people’s conspiracy beliefs is notoriously difficult,” said lead researcher Matthew Hornsey, PhD, of the University of Queensland. “An alternative possibility is to acknowledge the possibility of conspiracies, but to highlight how there are vested interests on the other side too; vested interests that are motivated to obscure the benefits of vaccination and to exaggerate their dangers.” 

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