People in high-income countries have the lowest confidence in vaccines, with about 20% of those in Europe either disagreeing or being unsure of whether vaccines are safe, according to a new global survey.
The Wellcome Trust, a UK medical research charity, asked more than 140,000 people ages 15 and older in more than 140 countries how they think and feel about health and science.
Globally, about 8 in 10 people (79%) agreed that vaccines are safe, and 9 in 10 worldwide say their children have been vaccinated, but Wellcome said there were pockets where trust in vaccines was of concern.
"Vaccines, for example, are one of our most powerful public health tools, and we need people to have confidence in them if they are to be most effective," said Jeremy Farrar, director of the Wellcome Trust.
"No matter how great your idea, how exciting your new treatment or how robust your science, it must be accepted by the people who stand to benefit from it," he added.
Once largely eradicated in many places, measles has been making a comeback globally, including in the United States, in part due to backlash against immunization among some groups. In addition to poor health infrastructure and lack of awareness, social media has made it easier for vaccine opponents to operate.
France most skeptical about vaccines
The survey found that Bangladesh and Rwanda had the strongest confidence in vaccines. Almost all people in both countries agree that vaccines are safe, effective and important for children.
In high-income regions, however, there is less certainty about the safety of vaccines, with 72% of people in North America agreeing that vaccines are safe. In Europe, that figure is even lower: 59% in Western Europe and 40% in Eastern Europe.
"And in some of these regions, greater scientific knowledge or levels of education is actually associated with less confidence in vaccines," the report says. "This suggests that putting out more scientific information, or trying to educate more people, will not be enough to change minds on this issue."
The report singled out France as having the lowest levels of trust in vaccines. One-third of its inhabitants don't agree that vaccines are safe, and one-tenth don't agree that they are important for children to have.
"The rising vaccine hesitancy in France over the past several years -- which even now includes some members of the medical community -- has helped drive vaccine coverage among some children and young adults below immunity thresholds and led to rising numbers of measles and meningococcal disease cases, " the report says.
It adds that more research is needed into the role that social media and misinformation campaigns have played in generating skepticism around vaccination.
"Anxieties and public concerns about the safety of vaccines have always existed, but the rise of social media has allowed the spread of what UNICEF calls the 'real infection of misinformation' to much wider audiences," the report says.
The survey found that three-quarters of the world's population (73%) trust doctors and nurses more than anyone else for health advice. A similar number of people (72%) trust scientists.
More than half of the population don't think they know much -- if anything -- about science, though men were more likely to claim greater scientific knowledge than women.
Globally, 49% of men worldwide say they know "some" or "a lot" about science, compared with 38% of women. The gap was largest in Northern Europe, where 75% of men claim to know "a lot" or "some" science, compared with just 58% of women. The gap was narrowest in the Middle East and Southeast Asia.