The United States is confronting its worst measles outbreak in over three decades, with more than 4,400 reported cases and at least three deaths so far this year. The surge follows a 2025 tally of nearly 2,300 cases and has prompted public‑health experts to warn that the disease’s return is a symptom of deeper systemic weaknesses.
Rising cases and vaccination gaps
Measles, one of the most contagious viruses, is preventable with a safe, highly effective vaccine. Yet the Centers for Disease Control and Prevention (CDC) reports that kindergarten‑age vaccination coverage for the measles‑mumps‑rubella (MMR) series fell to 92.4% in the 2025‑2026 school year, below the 95% threshold needed to halt sustained transmission. That shortfall translates to roughly 280,000 children who have not completed the two‑dose series.
Exemptions for childhood vaccines reached a record high of 4.2% among incoming kindergarteners, up from 3.6% the prior year. A September NBC News investigation found that 67% of U.S. counties and jurisdictions now report MMR immunization rates below 95%, creating pockets where the virus can spread unchecked.
“The bottom line is that not enough people are vaccinating their kids,” said Jennifer Nuzzo, an epidemiology professor and director of the Pandemic Center at Brown University School of Public Health. Nuzzo added that while most Americans continue to support childhood vaccines, a sizable “uncertain middle” leaves many families vulnerable to misinformation.
Policy and public‑health challenges
Policy moves this year have compounded the problem. In August, former President Donald Trump signed an executive order proposing to split the combined MMR vaccine into separate shots and repeated false safety claims. Health and Human Services Secretary Robert F. Kennedy Jr. also reshaped a federal advisory committee on childhood immunizations, though those changes remain frozen amid litigation.
Public‑health infrastructure has also suffered. Virologist Scott Weaver, research director at Galveston National Laboratory, noted that the CDC lost many experienced scientists and physicians during the COVID‑19 pandemic, weakening its capacity to monitor vaccine‑preventable diseases. As of September, the CDC stopped immediately adding state‑reported measles‑associated deaths to its national tally, listing only three deaths for 2026 despite Pennsylvania alone reporting at least five.
“We have folks in federal health leadership right now that are throwing gasoline on the fire, and that is not helping the situation,” said Jess Steier, founder and CEO of Unbiased Science.
Potential future scenarios
Modeling published in JAMA in April 2025 warns that if current vaccination rates persist, measles could become endemic in the United States, potentially causing 851,300 cases, 170,200 hospitalizations and 2,550 deaths over a 25‑year span. The model assumes periodic introductions of the virus by unvaccinated travelers, a scenario already observed in recent outbreaks.
Comparisons to Canada underscore the risk. Canada lost its measles elimination status in November after a multi‑province outbreak produced more than 5,400 cases in 2025. Epidemiologist Michael Osterholm cautioned that a similar trajectory could generate up to 50,000 U.S. cases.
Declining coverage is not limited to measles. The CDC reports that polio vaccination among kindergarteners fell to 92.4% and DTaP coverage slipped to 92% in the same school year. Pertussis (whooping cough) cases have risen sharply, reaching roughly 43,300 in 2024 and nearly 28,000 in 2025, reflecting both waning immunity and lower uptake.
In a hypothetical scenario where childhood vaccination rates dropped by half, the same JAMA model projected millions of cases of other once‑controlled diseases, including 9.9 million rubella cases, 4.3 million polio cases and 197 diphtheria cases over 25 years.
As the Pan American Health Organization prepares to review the United States’ measles elimination status in Washington, D.C., in mid‑November, officials face a stark choice: reinforce vaccination programs and public‑health capacity, or risk a return to endemic transmission of measles and other vaccine‑preventable illnesses.
Helene Elliott is the Lead Science & Space Reporter at News Raise. She reports on aerospace missions, astrophysics discoveries, quantum research, and environmental technology.
