Most Parents Haven’t Heard Misinformation About the Measles Vaccine though Significant Shares Are Uncertain About the Validity of Claims

As rates of childhood vaccination decline and with measles on the rise again, a KFF Health Misinformation Tracking Poll, fielded in late February, examines the extent to which adults have heard and believe misinformation about the measles vaccine. The poll also examines the public’s views of the U.S. government and social media companies’ role in moderating false health claims online.

While most of the public—including parents—haven’t heard misinformation about the measles vaccine, many are uncertain about the validity of one specific false claim. About one in five adults (18%, including 19% of parents of children under age 18) say they have heard or read the claim, “Getting the measles vaccine is more dangerous than becoming infected with measles.”

A relatively small share leans towards believing the claim is true. Regardless of whether they have heard the claim, a fifth of adults (19%), including one quarter of parents (25%), say the claim is “definitely” or “probably” true. Six percent of U.S. adults—including about one in ten (9%) parents—say they have heard the claim and think it is probably or definitely true.

Across partisans, levels of educational attainment, and race and ethnicity, fewer than five percent of adults say that the claim is “definitely true,” meaning that there are few ardent believers in this piece of misinformation. However, independents (37%) and Republicans (21%) are less likely than Democrats (59%) to be certain that the claim is “definitely false.” Those without a college degree (29%) are also less likely to say that the claim is false than those with a college degree (55%).

Large Shares Support Social Media Companies in Restricting Health Misinformation at the Expense of Certain Freedoms

Later this March, the Supreme Court will hear arguments in three important cases related to misinformation on social media that will have implications for how the U.S. government and social media companies interact with users and can moderate information.

Two-thirds (68%) of the public views the spread of health misinformation on social media as a bigger problem than censorship of speech on social media platforms (31%). This sentiment is in turn reflected in opinions about what kind of action social media companies should take to curb the spread of false health claims.

Large shares of the public support social media companies in tamping down on misinformation even at the expense of certain freedoms. About two-thirds (66%) of adults overall say, “Social media companies should restrict false health information, even if it limits people from freely publishing or accessing information,” while one-third instead say “People’s freedom to publish and access health information should be protected, even if it means false information can also be published.”

The public is more divided about whether the U.S. government should take action. Nearly six in ten adults overall (57%) say, “The U.S. government should require social media companies to take steps to restrict false health information, even if it limits people from freely publishing or accessing information,” while about four in ten (42%) say “People’s freedom to publish and access health information should be protected, even if it means false information can also be published.”

There are partisan divisions on both these questions, with Democrats more likely than independents or Republicans to favor both the government and social media companies taking action to restrict false health information. Notably, however, majorities of Democrats (82%), independents (57%), and Republicans (56%) say that social media companies should take steps to restrict health misinformation even if it limits certain freedoms.

The Health Misinformation Tracking Poll is part of a new KFF program area focused on identifying and monitoring health misinformation and trust in the United States, emphasizing communities that are most adversely affected by misinformation, including people of color, immigrants, and rural communities.

Designed and analyzed by public opinion researchers at KFF, the poll was conducted from February 20-28, 2024, online and by telephone among a nationally representative sample of 1,316 U.S. adults including 283 parents. Interviews were conducted in English and in Spanish. The margin of sampling error is plus or minus 3 percentage points for the full sample and 7 percentage points for the sample of parents. For results based on other subgroups, the margin of sampling error may be higher.