Record measles cases and rising childhood vaccine exemptions in the U.S. have fueled concerns that Americans are increasingly turning against vaccines.
But the reality may be more complicated than that.
The biggest challenge for public health officials trying to contain deadly diseases may not be widespread anti-vaccine sentiment or the influencers and political figures who spread it. Only a small share of Americans indicate they firmly believe common myths about the shots, according to a survey released in July by health policy research organization KFF.
Many other Americans fall into a large, uncertain middle ground — neither firmly pro-vaccine nor staunchly opposed — where they have questions or anxieties about shots and may be susceptible to conflicting messages about their safety and effectiveness.
KFF presented adults with four common vaccine myths. Fewer than 1 in 10 respondents said each claim was definitely true. But at least half fell into a gray area, saying the claims were either "probably true" or "probably false."
"What's more true is a lot of people are confused," Drew Altman, KFF CEO and founding president, said in an interview. "They don't know who to believe, they don't know what to believe, and that means that a lot of America is stuck in the middle, unsure and they're up for grabs."
That uncertainty could pose a growing public health hazard as the Trump administration reshapes federal vaccine policy and health officials grapple with declining immunization rates for some shots. Vaccine misinformation has a larger megaphone than ever with Trump in the White House: Earlier this month, without evidence, he linked the measles-mumps-rubella vaccine to autism, as he called for splitting the routine childhood immunization into separate shots.
People who are confused about vaccines may become "paralyzed" and delay or avoid decisions such as whether to immunize their children, Altman said.
The majority of Americans still get themselves and their children vaccinated, but "even little dips in that coverage could lead to more of a highly contagious virus like measles circulating," said Jess Steier, a public health scientist and founder and CEO of Unbiased Science, which specializes in making complex scientific concepts understandable.
Still, she emphasized that while people with questions about vaccines may be susceptible to misinformation, they can also be reached through clear, evidence-based information and conversations with trusted healthcare providers.
"Uncertainty can resolve once people have time, information and access," she added.
Vaccine hesitancy is much more complicated than outright opposition to vaccines, Steier said. Social media and the current political environment only fuel more of the confusion, she added.
People are often exposed to emotionally charged, alarming content online because social media algorithms tend to amplify it, Steier said. As a result, many people are encountering conflicting messages about vaccines and struggling to determine which sources are trustworthy. Rather than being firmly anti-vaccine, many are simply overwhelmed by competing information, she said.
Some of that messaging comes from political leaders such as Trump and Health and Human Services Secretary Robert F. Kennedy Jr., which makes the challenge facing other public health officials tougher. Kennedy has frequently said that he is not "anti-vaccine," but he has a well-documented history of spreading scientifically inaccurate information around vaccine safety and efficacy.
Based on years of reviewing comments, questions and survey responses from people engaging with Unbiased Science's social media platforms, the company developed a framework for understanding vaccine hesitancy. A narrower version named "LANDS" was specifically developed for pharmacists in partnership with the National Alliance of State Pharmacy Associations, as most adult vaccinations now occur at pharmacies, Steier noted.