KFF Tracking Poll on Health Information and Trust: The Public’s Views on Measles Outbreaks and Misinformation

Key Findings

• As the U.S. grapples with rising measles cases across multiple states and the highest number of cases since 2019, about half of adults (51%) and parents (47%) say they are at least "somewhat worried" about the outbreak of measles, including roughly one in seven adults who are "very worried" (14% of all adults, 13% of parents). Concern is notably higher among Black and Hispanic adults - six in ten of each group express worry compared to 46% of White adults. Roughly half of adults (56%) and parents with children under 18 (48%) are aware that the number of U.S. measles cases is higher this year than in recent years.
• Partisanship plays a major role in whether people are aware that measles cases are on the rise and whether they are worried about the most recent outbreak. Democrats are much more likely than Republicans to say they are worried about the outbreak of measles in the U.S. (76% v. 28%), and to know measles cases are up this year compared to recent years (71% v. 49%). Similar partisan gaps exist among parents as well, with Democratic and Democratic-leaning parents more than twice as likely as Republican and Republican-leaning parents to express worry over the outbreak of measles (73% v. 26%) and more likely to know the number of cases is currently higher than in past years (64% v. 37%).
• Most adults and parents say they have read or heard some false claims about measles or the measles, mumps, rubella (MMR) vaccines, some of which have been amplified by Robert F. Kennedy Jr., the U.S. Secretary for Health and Human Services. The most pervasive myth is the false link between autism and the measles vaccines, with about six in ten adults (63%) and a similar share of parents (61%) saying they have read or heard the false claim that the MMR vaccines have been proven to cause autism in children.
• The share of adults who report having heard or read the false claim that the measles vaccines are more dangerous than being infected with measles has increased by 15 percentage points in the past year. One in three adults now say they have heard or read the false claim that getting the measles vaccine is more dangerous than becoming infected with measles, up from 18% in March 2024. The shares who report having heard this false claim have also increased across partisans in the past year and more than doubled among Democrats (40% now compared to 17% in 2024).
• When it comes to false claims that the MMR vaccines have been proven to cause autism, that vitamin A can prevent measles infections, or that getting the measles vaccine is more dangerous than becoming infected with measles, less than 5% of adults say they think these claims are "definitely true," and much larger shares say they are "definitely false." However, at least half of adults are uncertain about whether these claims are true or false, falling in the "malleable middle" and saying each claim is either "probably true" or "probably false." While at least half of adults express some level of uncertainty, partisans differ in the shares who say each of these false claims is definitely or probably true, with Republicans and independents at least twice as likely as Democrats to believe or lean towards believing each false claim about measles. One-third of Republicans (35%) and a quarter (26%) of independents say it is "definitely" or "probably true" that the MMR vaccines have been proven to cause autism, compared to one in ten Democrats; three in ten Republicans (29%) and independents (28%) say it is "definitely" or "probably true" that vitamin A can prevent measles infections compared to 14% of Democrats; and one in five Republicans (20%) and independents (21%) believe or lean toward believing that the measles vaccine is more dangerous than measles infections compared to about one in ten (11%) Democrats.
• Even amid widespread exposure to false claims about measles, large majorities of the public (83%) and parents (78%) say they are "very" or "somewhat confident" that the MMR vaccines are safe. However, confidence in the safety of MMR vaccines is lower among Republican and Republican-leaning parents, with about three in ten (31%) expressing a lack of confidence in the safety of MMR vaccines, including about one in six (17%) who say they are "not at all confident" the MMR vaccine is safe.

Awareness and Worry About Measles Outbreaks in the U.S.

As of late April, the U.S. has confirmed 800 measles cases in 2025 across more than 20 states - already more than double the amount of cases reported in 2024. KFF's latest Tracking Poll on Health Information and Trust finds that most adults (56%) and about half of parents of children under 18 (48%) are aware that the number of measles cases in the U.S. is higher this year than in recent years. This leaves about four in ten adults who are unaware that measles cases are on the rise in the U.S., either incorrectly saying cases are lower or about the same as compared to recent years (16%), or that they are "not sure" (28%).

Awareness of the rise in measles cases differs across partisans, as Democrats are much more likely than Republicans to know that measles cases are higher this year than recent years (71% v. 49%), with a similar partisan gap occurring among parents who are Democrats or lean Democrat and those who are Republicans or lean Republican (64% v. 37%). Overall, college graduates are more likely than those without a college degree to know that measles cases are up this year compared to recent years (72% vs. 47%), but partisan differences in knowledge hold even when controlling for education. For example, among adults without a college degree, a larger share of Democrats than Republicans are aware that measles cases are higher now than in recent years (61% v. 43%). These partisan differences may be related to messaging from the Trump administration as Health and Human Services Secretary Robert F. Kennedy Jr. has recently claimed this year's outbreak in the U.S. is "not unusual" even as measles cases in the U.S. are currently at their highest point since 2019.

Half of adults (51%) and a similar share of parents (47%) say they are at least "somewhat worried" about the outbreak of measles in the U.S., including 14% of adults and 13% of and parents who say they are "very worried." Concern about measles is also higher among Black adults and Hispanic adults, with about six in ten of each group saying they are worried compared to about half (46%) of White adults. Just as Democrats are more aware of the rise in measles cases, they are also more worried about the current outbreak. Democrats are more than twice as likely as Republicans to say they are worried about the outbreak of measles in the U.S. (76% v. 28%), while a similar partisan split exists among parents (73% v. 26%). These large partisan differences persist when controlling for education; among both college graduates and those without a degree, the share who express worry is at least twice as large among Democrats as among Republicans.

Misinformation About Measles and Vaccines

As attitudes toward childhood vaccination shift alongside declining childhood vaccination rates, false and misleading statements about measles and the measles, mumps, rubella (MMR) vaccines have continued to spread. While current Health and Human Services Secretary Robert F. Kennedy Jr. has recently recommended people get the MMR vaccines, he has also recently claimed the MMR vaccines cause the same illnesses that measles itself causes and touted vitamin A as a potential remedy for measles, which has led to concerns that some may turn to supplements in lieu of vaccination. Kennedy also has a history of linking vaccines and autism, a claim associated with a since-retracted study in the 1990s.

The latest KFF Tracking Poll on Health Information and Trust finds most adults and parents say they have read or heard some false claims about measles or the MMR vaccines - with the link between the MMR vaccine and autism the most prevalent. About six in ten adults (63%) and parents (61%) say they have read or heard the false claim that the MMR vaccines have been proven to cause autism in children. The share of adults and parents who say they have heard this false claim has remained persistent and largely unchanged since 2023. About seven in ten White adults (72%) say they have heard the false claim linking the MMR vaccines with autism, compared to fewer Black adults (53%) and Hispanic adults (45%). The share of adults who report hearing this false claim includes majorities across gender, age and partisanship.

One-third of adults and parents have heard or read the false claim that getting the measles vaccine is more dangerous than becoming infected with measles, and one in five adults and similar shares of parents (17%) have heard or read the false claim that Vitamin A can prevent measles infections. About a quarter of Democrats (26%) and independents (23%) say they have heard that vitamin A can prevent measles infections compared to fewer Republicans (13%); however, among parents, similar shares across partisans report having heard this claim.

Notably, the shares of adults and parents who have heard the false claim that the measles vaccine is more dangerous than getting infected with measles has increased by 15 percentage points since March 2024, when about one in five adults (18%) and parents (19%) reported having heard this claim. The share who reports having heard this claim has also increased across partisans since 2024 and doubled among Democrats (40% now compared to 17% in 2024).

Belief in False Claims About Measles and Vaccines

Even with widespread exposure to some false claims about measles, less than 5% of adults say they think each claim is "definitely true." Yet, less than half of adults say each of these claims is "definitely false," with larger shares expressing some doubt. Similar to what previous KFF polls have found on a wide range of health misinformation topics, many adults fall into a "malleable middle" category, expressing uncertainty about the veracity of these claims. At least half the public fall into this malleable middle category when it comes to false statements about measles, saying it is either "probably true" or "probably false" that vitamin A can prevent measles infections (70%), that the MMR vaccines have been proven to cause autism in children (62%), or that measles vaccines are more dangerous than measles infections (54%).

While most people express some level of uncertainty, there are differences by partisanship, education and race/ethnicity in the shares who believe or lean toward believing each of these false claims. A quarter of adults and one-third of parents (33%) say the false claim that MMR vaccines have been proven to cause autism in children is either "definitely true" or "probably true." Similarly, a quarter of adults (24%) and about three in ten parents (31%) say it is "definitely" or "probably true" that vitamin A can prevent measles infections. Fewer, but still notable shares (19% of adults, 27% of parents), endorse the claim that MMR vaccines are more dangerous than measles infections.

At least one in five Republicans and independents say they think each of the three false claims about measles are either "definitely" or "probably true" compared to smaller shares of Democrats, including that the MMR vaccines have been proven to cause autism in children (35% of Republicans and 26% of independents compared to 10% of Democrats), that vitamin A can prevent measles infections (29% of Republicans and 28% of independents v. 14% of Democrats), and that the measles vaccine is more dangerous than measles infections (20% of Republicans and 21% of independents v. 11% of Democrats). These partisan divisions also hold among parents, with Republican or Republican-leaning parents consistently more likely than Democratic or Democratic-leaning parents to say the false claims are "definitely" or "probably true."

While adults without a college degree are about twice as likely as those with a college degree to believe or lean toward believing each false claim, partisan differences hold even when controlling for education in most cases. For example, among adults without a college degree, Republicans are three times as likely as Democrats to say it is "definitely" or "probably true" that the MMR vaccines are proven to cause autism (41% v. 13%), and among those with a college degree, Republicans continue to be more likely than Democrats to believe or lean toward believing the myth (25% v. 5%).

Hispanic adults are more likely than Black adults and White adults to say it is "definitely" or "probably true" that the measles vaccine is more dangerous than becoming infected with measles (34% of Hispanic adults v. 19% of Black adults and 15% of White adults) or that Vitamin A can prevent measles infections (43% of Hispanic adults v. 25% of Black adults and 18% of White adults). Similar shares across race and ethnicity say it is "definitely" or "probably true" that the MMR vaccines are known to cause autism.

The share of adults who say it is "definitely true" or "probably true" that the MMR vaccines are linked to autism in children or that the MMR vaccines are more dangerous than measles has not changed since 2023 or 2024, respectively, including among parents and across partisan groups.

Believing or leaning toward believing false claims about measles and MMR vaccines is associated with parents' actions when it comes to vaccinating their children. Among parents who say that at least one of the three false claims about measles is either "definitely" or "probably true," a quarter (24%) say they have delayed or skipped some vaccines for their children, compared to about one in ten parents (11%) who say each of the three measles myths are "probably" or "definitely false." While belief in false claims about measles is associated with parents delaying or skipping some vaccines for their children, the survey did not measure whether they have skipped the MMR vaccine specifically.

Views on the Safety of MMR Vaccines

Even amid widespread exposure to some false information about the MMR vaccines, large majorities of adults and parents are confident the measles, mumps, rubella (MMR) vaccines are safe, though confidence is notably lower among Republican and Republican-leaning parents. At least eight in ten adults (83%) and parents (78%) say they are either "very" or "somewhat confident" that vaccines for measles, mumps, and rubella are safe, with over nine in ten Democrats (96%) and eight in ten independents (80%) and Republicans (79%) expressing confidence. While confidence in MMR vaccine safety is high among Democratic and Democratic-leaning parents (95%), far fewer Republican and Republican-leaning parents are confident in the safety of the MMR vaccines (69%) - leaving three in ten Republican parents who say they are not confident in the safety of the measles vaccines, including about one in six who say they are "not at all confident" (17%). The MMR vaccines have been proven to be both safe and effective in providing protection against measles.