Measles once seemed like a problem of the past. In 2000, the United States eliminated endemic transmission. More than two decades later, however, the virus is spreading again, fueled by misinformation and declining vaccination coverage.
As of October 15, 2026, the CDC reported 4,410 measles cases in the United States. That was nearly double the 2,289 cases reported in 2025, which marked the worst year since 1991, and more than 15 times the 285 cases recorded in 2024. About 95% of cases involved unvaccinated people or those whose vaccination status was unknown. This November, the Pan American Health Organization is expected to decide whether the US keeps its measles “elimination status,” which Canada lost in 2025.
About 10% of those infected required hospitalization, and the CDC has confirmed two deaths. Pennsylvania authorities reported five deaths linked to the outbreak and were reviewing a sixth death in October. The discrepancy reflects different criteria for attributing deaths to measles.
Vaccination coverage for measles, mumps, and rubella (MMR) among kindergarten-aged children fell from 95.2% in the 2019–2020 school year to 92.4% in 2025–2026, below the CDC “herd immunity” threshold of 95%. National averages, however, mask local pockets of low vaccination coverage.
Measles Is More Than a Childhood Rash
Although measles may seem like a mild illness, it can cause serious complications:
- One in five unvaccinated people who contract measles requires hospitalization.
- One in 20 infected children develops pneumonia.
- One in 1,000 infected children develops encephalitis, an infection of the brain, which can cause seizures, deafness, or intellectual disability.
- One to three in every 1,000 infected children die from complications.
Given this situation, it’s important to examine what could happen if current trends continue, how misinformation contributes to vaccine hesitancy, and, most importantly, what we can do about it.
Misinformation Meets Mistrust
Factors associated with MMR vaccine hesitancy include safety concerns, fear of needles, institutional distrust, and false beliefs, such as the alleged link between the vaccines and autism.
A 2026 study published in Vaccine examined how media preferences related to vaccine hesitancy during measles outbreaks in the United States in 2025. The researchers surveyed 2,970 adults. Approximately 17% believed the risks of the MMR vaccine outweighed its benefits. Following "new right" media outlets, such as Breitbart, was associated with twice the odds of MMR vaccine hesitancy, while seeking health information from digital influencers and alternative medicine practitioners was associated with a slightly lower risk. By contrast, consulting medical doctors was associated with the least hesitancy.
Similarly, a 2026 scoping review published in the Journal of Pediatric Nursing analyzed 23 articles on misinformation and MMR vaccine hesitancy. The studies identified false claims about autism and other alleged vaccine risks circulating through social and religious groups, social media, internet searches, and films. The review found that communication interventions targeting vaccine hesitancy had achieved limited success, highlighting how difficult it can be to change vaccine attitudes.
These findings point to several influences on vaccine hesitancy, from misleading information online to distrust in institutions and beliefs about vaccine safety. Because claims about autism remain a reason some parents hesitate to vaccinate their children, it is worth examining how this false claim originated.
The Autism Myth That Refuses to Die
In 1998, former British physician Andrew Wakefield and his colleagues published a study in The Lancet that suggested a link between the MMR vaccine, gastrointestinal disorders, and autism. The study examined only 12 children, and subsequent studies failed to substantiate the alleged link between the MMR vaccine and autism. Investigations also uncovered ethical violations, data irregularities, and undisclosed conflicts of interest. In 2010, The Lancet retracted the paper, and the UK’s General Medical Council revoked Wakefield’s medical license.
Despite this, the alleged link continues to fuel vaccine hesitancy.
When Public Health Speaks With Mixed Messages
Public health officials should clearly communicate the benefits of vaccination and the risks of measles. However, their messages do not always convey a consistent position.
In a March 2025 opinion piece, Kennedy claimed that improvements in sanitation and nutrition had eliminated 98% of measles deaths before the vaccine became available. A historical study in Epidemiology & Infection, which examined records from Scotland, New Zealand, and several Australian states, found that measles mortality had indeed declined before vaccines and antibiotics; however, the reasons for this decline remain uncertain. Although improved nutrition has been proposed as an explanation, the study highlights other possible factors, including changes in the age at infection, epidemiological isolation, and viral virulence.
During a CNN interview on August 2, 2026, US Health and Human Services Secretary Kennedy urged parents to vaccinate their children against measles, stating that the vaccine prevents the disease in about 97% of cases. He denied responsibility for the outbreak, blaming missed vaccinations during COVID-19 lockdowns, religious communities with low coverage, and outbreaks abroad.
Eight days later, President Trump signed an executive order recommending splitting the MMR vaccine into three single-disease shots, which are not currently available in the US. The CDC has said no published evidence shows any benefit to separating it.
One survey offers a different perspective on how Americans perceive Kennedy’s position. In an Annenberg Public Policy Center survey of 1,904 American adults conducted in August 2026, 31% said Kennedy recommended childhood measles vaccination, up from 23% in August 2025. Another 29% said he did not recommend it, while 40% were unsure.
In the same survey, 55% agreed with the American Academy of Pediatrics' view that studies have found no credible link between childhood vaccines and autism. In comparison, 18% agreed with the CDC website's language, changed in November 2025, calling the claim that vaccines do not cause autism not evidence-based.
The survey does not establish that Kennedy’s statements caused this confusion. Yet, it shows that a substantial proportion of the public remained uncertain about his position despite his explicit call for parents to vaccinate their children.
The Human Cost of Falling Vaccination Rates
A commentary published in Public Health Reports noted that annual measles vaccination coverage remains below the estimated 95% threshold for herd immunity. Their models suggested a 10% decline in vaccination could increase the proportion of susceptible children and adolescents from 13.5% to 21.4%.
What happens if vaccination rates fall even further?
A 2025 study published in JAMA modeled [1] how declining childhood vaccination could bring back measles, rubella, polio, and diphtheria in the United States. The model has several limitations, including simplifying real-world transmission and using uncertain surveillance data.
However, at current state-level vaccination rates, measles could become endemic again over the next 25 years. A 10% decline in MMR vaccination increases measles cases and further shortens the interval to endemicity.
Rebuilding Trust, One Conversation at a Time
A systematic review published in Vaccine examined 33 communication interventions targeting parental vaccine hesitancy. In-person, interactive formats appeared most promising, aligning with the central role healthcare professionals play in providing accurate information about vaccine safety and effectiveness in a welcoming environment where parents feel comfortable expressing their concerns.
The return of measles is not a failure of vaccine science. The evidence for the MMR vaccine's safety and effectiveness remains strong. Instead, it warns what happens when misinformation, declining institutional trust, and inconsistent public health messaging converge. Reversing that trend will require more than correcting false claims. It will require clear, consistent communication from public health leaders and patient, evidence-based conversations between healthcare professionals and the families they serve.
For those of us who do not shape public policy, while we cannot single-handedly restore trust in public health institutions, we can challenge misinformation when we encounter it, distinguish legitimate questions from demonstrably false claims, and recognize that listening may be as important as correcting. This is a practical solution that does not require ‘’reshaping education to teach critical thinking " or ‘’criminalizing anti-vaccine speech online.’’
[1] The model used state-level vaccination estimates from 2004 to 2023 and accounted for age-specific social contacts, birth rates, vaccine efficacy, imported infections, and disease complications. The researchers modeled each pathogen and state separately, without allowing transmission between states.
Mauro Proença
Mauro Proença is a nutrition graduate student with a postgraduate degree in Clinical Nutrition from the University of São Paulo (USP), Brazil.
