Measles Comeback Reveals Cracks in America's Public Health Defenses, Experts Warn

More than 4,400 measles cases and at least three deaths have been reported across the United States this year, the country's worst outbreak in more than three decades. The surge follows nearly 2,300 cases in 2025. For many public health experts, the numbers are only part of the concern. They say the return of a disease the nation eliminated more than 20 years ago signals deeper problems.

Jennifer Nuzzo, an epidemiology professor and director of the Pandemic Center at Brown University School of Public Health, called measles "the canary in the coal mine" for other vaccine-preventable illnesses and for sudden, dangerous infectious disease emergencies. She was one of 10 experts CNBC interviewed about the outbreak. The U.S. is on track to lose its official elimination status when the Pan American Health Organization meets in Washington in mid-November.

The tools to stop the virus exist. The measles, mumps and rubella vaccine is about 97% effective after two doses and 93% effective after one, according to the Centers for Disease Control and Prevention. Yet kindergarten coverage for the shot fell to 92.4% in the 2025-2026 school year, below the 95% level officials generally say is needed to prevent sustained spread. That leaves 280,000 kindergarteners without a completed series. Exemptions reached a record 4.2%, up from 3.6% the year before.

Pockets of low coverage are a major factor. A September NBC News investigation found that 67% of counties and jurisdictions in states collecting MMR data have rates under 95%. Dr. William Moss of the Johns Hopkins Bloomberg School of Public Health said recent outbreaks have often struck closely knit communities with frequent contact and low vaccination. Nuzzo noted that most parents still vaccinate their children, and a July KFF survey found many Americans are uncertain rather than opposed, which leaves room for conflicting information to sway them.

Federal policy is adding to the worry. President Donald Trump signed an executive order in August suggesting the MMR vaccine be split into separate shots, while repeating false claims about its safety. Health and Human Services Secretary Robert F. Kennedy Jr. has overhauled the federal advisory committee that recommends childhood immunizations, though those changes are frozen amid litigation. Scott Weaver, research director of Galveston National Laboratory, said the CDC also lost many experienced vaccine scientists, and as of September it no longer immediately adds state-reported measles-associated deaths to its national tally. The CDC lists three deaths in 2026, while Pennsylvania has reported at least five.

Looking ahead, a model published in JAMA in April 2025 by Stanford researchers and others estimated that, at current state-level vaccination rates, measles could become endemic again, causing about 851,300 cases, 170,200 hospitalizations and 2,550 deaths over 25 years. Michael Osterholm of the University of Minnesota pointed to Canada, which lost its elimination status in November after more than 5,400 cases in 2025. Scaled to the U.S. population of 350 million, he said, a similar experience could mean up to 50,000 cases.

Other diseases are also affected. Kindergarten polio coverage fell to 92.4% and DTaP coverage to 92%. Whooping cough cases reached roughly 43,300 in 2024 and nearly 28,000 in 2025. The JAMA model found rubella and polio unlikely to become endemic at current levels, but a hypothetical 50% drop in childhood vaccination produced projections of 9.9 million rubella cases, 4.3 million polio cases and 197 diphtheria cases over 25 years. The researchers stressed these are not predictions.

Experts also see implications for readiness. Dr. Manisha Juthani, president of the Association of State and Territorial Health Officials, said the country must keep investing in surveillance because diseases do not respect borders. Osterholm cautioned that low MMR rates do not necessarily mean Americans would refuse a vaccine or antibiotic in a biological emergency. The measles resurgence alone cannot show how the country would handle a new threat, but experts say the stakes reach well beyond this one disease.