THURSDAY, Feb. 1, 2018 (HealthDay News) -- Think vaccines aren't safe? If so, you might also believe that Princess Diana was murdered.
That's the finding of new research into the relationship between conspiracy theory beliefs and anti-vaccination attitudes.
A survey of more than 5,300 people in 24 countries on five continents found that people who believe in conspiracy theories are more likely to believe that vaccines aren't safe, despite scientific evidence to the contrary.
The study findings were published Feb. 1 in the journal Health Psychology.
"Vaccinations are one of society's greatest achievements and one of the main reasons that people live about 30 years longer than a century ago," said the study's lead researcher, Matthew Hornsey, from the University of Queensland in Australia.
"Therefore, it is fascinating to learn about why some people are so fearful of them," he said in a journal news release.
Survey participants were asked their beliefs about vaccination and their thoughts on four conspiracy theories: that Princess Diana was murdered; that the U.S. government knew about the 9/11 attacks in advance and allowed them to happen; that a shadowy group of elites is plotting to create a new world order; and that there was an elaborate plot to assassinate President John F. Kennedy that has been covered up.
What the researchers found was that people most likely to oppose vaccination were those who strongly believed in conspiracies. That held true no matter where the people lived. Education levels also had little effect on attitudes about vaccination.
People with anti-vaccination attitudes also were found to be intolerant of limits on their freedom, and uneasy about blood and needles. They also were described as having an individualistic worldview.
"People often develop attitudes through emotional and gut responses," Hornsey said. "Simply repeating evidence makes little difference to those who have anti-vaccination attitudes."
He noted that a common target of conspiracy theorists is large drug companies, because they make money selling vaccines.
"For many conspiracy theorists, profits gained are a sign that the system is broken and the truth is being covered up by vested interests," Hornsey said.
"Trying to reduce people's conspiracy beliefs is notoriously difficult," he added. "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."
The U.S. Centers for Disease Control and Prevention outlines 10 reasons to get vaccinated.