The United States is on track for another troubling year of measles outbreaks, with more than 1,100 cases reported so far in 2026, according to the U.S. Centers for Disease Control and Prevention (CDC). Public health officials warn that the highly contagious virus — once considered eliminated in the U.S. — is spreading largely among people who are unvaccinated.
One of the largest outbreaks this year has occurred in South Carolina, where more than 600 cases have been reported. Health officials there say the surge has been fueled by pockets of low vaccination rates, particularly in communities where measles-mumps-rubella (MMR) coverage has fallen well below the level needed to prevent spread.
But outbreaks are not limited to one state. More than half of U.S. states have reported measles cases in 2026.
In 2025, both Kansas and Missouri experienced measles outbreaks. Kansas reported a cluster of cases in southwest counties, while Missouri confirmed cases tied to local transmission. Though those outbreaks were eventually contained, public health officials warned that declining vaccination rates leave communities vulnerable to renewed spread.
A Disease Once Eliminated
Measles was declared eliminated in the United States in 2000, meaning the virus was no longer spreading continuously within the country. That milestone followed decades of widespread vaccination and high community immunity.
The recent resurgence has largely been linked to falling immunization rates.
Measles is one of the most contagious viruses known. It spreads through the air when an infected person coughs or sneezes and can linger in a room for up to two hours. If one infected person enters a room of unvaccinated individuals, up to 90% of them can become infected.
And it is far from a mild childhood illness.
About one in five unvaccinated people who get measles will be hospitalized. Among children, about one in every 1,000 cases can lead to encephalitis — dangerous swelling of the brain that can cause deafness or intellectual disability. Up to three in every 1,000 infected children may die. Pneumonia is another common and serious complication, particularly in adults.
Last year, the United States recorded nearly 2,300 measles cases — the highest annual total since 1991. Three people died, all of whom were unvaccinated.
Why Vaccination Rates Are Falling
Public health experts say one of the biggest drivers of declining measles vaccination is the persistent — and repeatedly debunked — claim that the MMR vaccine is linked to autism.
That claim originated with a small 1998 study that was later found to be fraudulent and fully retracted. The lead author lost his medical license. Since then, large-scale studies involving hundreds of thousands of children across multiple countries have found no link between the MMR vaccine and autism.
Despite overwhelming scientific evidence, the autism myth continues to circulate widely on social media and in some political circles. Experts say many parents now fear vaccine side effects more than they fear measles itself.
The COVID-19 pandemic also disrupted routine pediatric visits, and some families fell behind on immunizations and never caught up. At the same time, several states have expanded religious or philosophical exemptions for school vaccinations, creating pockets of lower coverage.
Nationally, kindergarten MMR vaccination rates have slipped below the 95% threshold needed to maintain herd immunity in many areas.
CDC Recommendation Remains In Place
Despite broader debates about vaccine policy during President Donald Trump’s current term, the CDC has not changed its core recommendation for measles vaccination.
The agency continues to strongly recommend two doses of the MMR vaccine — the first at 12 to 15 months and the second at 4 to 6 years. Two doses are about 97% effective at preventing measles.
While the CDC has shifted language around some other vaccines to emphasize individualized decision-making between families and physicians, measles vaccination remains a routine recommendation.
Nearly all measles cases reported in recent years — about 96% this year — have occurred among people who were unvaccinated or had not received both recommended doses.
A Preventable Threat
Health experts warn that as long as vaccination rates remain uneven, measles outbreaks will continue to reappear.
Measles was eliminated once. It can be controlled again — but only if vaccination rates return to levels high enough to stop the virus from spreading.
For parents unsure of their child’s vaccination status, doctors recommend reviewing immunization records and speaking with a trusted healthcare provider.
Measles is preventable. The challenge now is rebuilding confidence in the protection that made elimination possible in the first place.