If someone vehemently argues that President John F. Kennedy's assassination was "an inside job," that Princess Diana was murdered or that the U.S. government knew about the attack on New York City's World Trade Center on Sept. 11, 2001, and declined to stop it, they might also skip vaccinations, according to a new study.
Researchers recently discovered a connection between beliefs in some conspiracy theories and mistrust of vaccines, and it appears across borders.
Their findings, described in a new study, are based on survey responses from thousands of people representing dozens of nations. The scientists were searching for clues to the psychology of anti-vaccination sentiments — despite scant evidence that vaccines are harmful — and they found that people who were the most distrustful of vaccines were also the ones with the strongest beliefs in certain conspiracy theories — regardless of their level of education. [Top 10 Conspiracy Theories]
Vaccines for preventable diseases have averted an estimated 2 million to 3 million deaths worldwide each year; and if global vaccination coverage were increased, approximately 1.5 million additional lives could be saved, according to the World Health Organization.
Numerous studies conducted over decades have shown vaccines to be both effective and safe, but anti-vaccination sentiments persist. The result: alarming drops in immunizations and the resurgence of diseases such as measles, pertussis and mumps in the U.S., researchers reported in the new study.
To understand what might cause people to reject vaccine science, the study authors conducted online surveys of 5,323 participants — about 50 percent male and 50 percent female — from 24 countries. In the surveys, questions addressed subjects' attitudes toward vaccines, conspiratorial beliefs, level of aversion to blood and needles, and whether their worldview favored individual freedom over shared responsibilities.
They found that people who expressed a distrust of vaccines also showed strong belief in conspiracy theories about the 9/11 terror attacks, and the circumstances surrounding the deaths of JFK and Princess Diana. Many people with anti-vaccination beliefs claim that vaccines are promoted unnecessarily by "Big Pharma" companies greedy for profit — another type of conspiracy theory, which could explain why they are receptive to other types of conspiracies, according to the scientists.
Survey subjects who were anti-vaccine also reported intense feelings of disgust or fear toward needles and blood, the study authors wrote.
A prior study indicated that belief in conspiracy theories is particularly strong and widespread in the United States. Of the people surveyed, more than 50 percent believe that the government is concealing what it knows about the 9/11 attacks, and nearly 50 percent feel the same about the JFK assassination, Live Science previously reported.
And once someone has embraced a conspiracy theory, it can be very difficult to change his or her mind — no matter how strong the evidence. Assertions that the Earth is flat, and that satellite images of a ball-shaped planet represent a NASA-perpetuated "round Earth conspiracy," have recently been embraced by celebrities such as former NBA star Shaquille O'Neal and rapper B.o.B, though there is ample, time-honored proof that Earth is, in fact, a sphere.
Instead of trying to convince anti-vaxxers that they're wrong about immunizations, it might be more productive to encourage them to consider the underlying motives of vaccines' opponents, study lead author Matthew Hornsey, a professor with the School of Psychology at the University of Queensland in Australia, said in the statement.
Highlighting "vested interests on the other side" could spark a conspiracy theorist's interest in learning who might benefit from exaggerating the dangers of vaccination and why they might mask the truth about vaccines' benefits, he said.
The findings were published online today (Feb. 1) in the journal Health Psychology.
Original article on Live Science.
Sign up for the Live Science daily newsletter now
Get the world’s most fascinating discoveries delivered straight to your inbox.
Mindy Weisberger is an editor at Scholastic and a former Live Science channel editor and senior writer. She has reported on general science, covering climate change, paleontology, biology, and space. Mindy studied film at Columbia University; prior to Live Science she produced, wrote and directed media for the American Museum of Natural History in New York City. Her videos about dinosaurs, astrophysics, biodiversity and evolution appear in museums and science centers worldwide, earning awards such as the CINE Golden Eagle and the Communicator Award of Excellence. Her writing has also appeared in Scientific American, The Washington Post and How It Works Magazine.