The United States has lost its measles elimination status, researchers with knowledge of the decision confirmed to CBS News partner KFF Health News on Saturday.
The decision from the Pan American Health Organization came after the U.S. recorded over 5,400 measles cases so far this year — more than double last year’s total. The Pan American Health Organization is a regional office for the World Health Organization, covering North and South America. The agency is set to hold a news conference on Tuesday.
A country is considered as having eliminated the measles if there are “no locally transmitted measles infections or outbreaks lasting 12 months or longer,” according to the World Health Organization.
The United States did not meet that standard for the first time since 2000. According to data from the Centers for Disease Control and Prevention, about a third of this year’s measles cases are linked to outbreaks that began in 2025 and continue to spread.
After a 30-year record of 2,242 cases last year, the CDC has tallied 5,412 cases to date in 2026, resulting in more than 590 hospitalizations and at least six measles-related deaths, with some states reporting additional fatalities.
The biggest outbreak has been in Pennsylvania, where state health officials have reported more than 1,500 cases and seven deaths associated with the disease this year. New York and Wisconsin have each reported one death.
Measles cases have been confirmed so far this year in 45 states and Washington, D.C.
What does it mean to lose measles elimination status?
A country or region loses its measles elimination status once its population immunity lowers enough that the disease’s spread can be sustained, CBS News medical correspondent Dr. Céline Gounder explained. When a country has measles elimination status and a high rate of vaccination, a case of measles or small outbreak will soon fizzle out. But when there are this many gaps in the population’s immunity, there can be “ongoing chains of transmission,” Gounder said.
“It means that we’re at risk of being exposed to measles and getting measles if we’re not vaccinated,” Gounder said. “It means ERs and pediatricians need to consider measles in anyone with a fever and rash, whether they’ve traveled overseas or not. And we may now become an exporter of measles to other countries.”
Dr. Omer Awan, a trained epidemiologist and senior public health contributor for Forbes, said that the loss of measles elimination status is a setback to the nation’s public health infrastructure.
“It’s frustrating and heartbreaking … because we have the tools to fight this. The tool is the MMR vaccine, which we know is 97% effective at preventing the onset of measles,” Awan said. “It’d be one thing if we didn’t have the tools to fight this, but the tools are at our disposal, we just aren’t using the tools that can help us mitigate the spread and beat measles.”
How can the U.S. regain measles elimination status?
A country earns measles elimination status by ensuring there is no local spread of the disease or outbreaks that last for more than a year.
PAHO says that the best way to maintain the elimination of measles is maintaining a vaccination rate of 95% or higher. Countries should also have sensitive surveillance systems to detect cases quickly, laboratory capacity and a guaranteed rapid response to outbreaks. Data about these trends must be submitted to and verified by the organization.
For the U.S. to curb outbreaks and regain measles elimination status, it needs to return to higher rates of vaccination, Awan said. He said battling misinformation and ramping up vaccination campaigns would be key to that effort.
Data shows childhood vaccination rates have declined in many communities around the U.S. in recent years, often below the threshhold needed to help ward off measles outbreaks.
Gounder also noted that lawmakers can create policies that lead to increased vaccination rates.
“States set the school vaccine rules. Nine states made opting out of vaccination easier in 2025. States ending nonmedical exemptions saw kindergarten vaccination rise 2 to 4 points,” Gounder said. “Most legislatures reconvene in January. Your state lawmakers will write next year’s exemption rules.”
Measles in the U.S.
The United States started collecting national data on measles in 1912, according to the Centers for Disease Control and Prevention. About 6,000 measles-related deaths were reported each year in the first decade of that data collection.
In the decade between 1953 and 1963, nearly all children in the U.S. caught measles before they turned 15, with an estimated 3 to 4 million people infected each year and tens of thousands hospitalized, according to the CDC. In those years, 400 to 500 people, mostly children, died of measles annually.
Then in 1963, the measles vaccine first became widely available. The numbers began a sharp decline and several generations of Americans grew up without ever encountering measles.
By 1981, reported measles cases had dropped by 80% compared to the previous year, the CDC said. The country was officially declared as having eliminated measles in 2000.
The U.S. maintained its elimination status for over 25 years. That didn’t mean there were no cases at all — in 2015, an outbreak that spread among unvaccinated people was traced back to overseas visitors at Disneyland in Southern California, and a 2018-19 outbreak in New York was eventually contained by public health measures including curtailing vaccine exemptions. But those spikes were just a fraction of the spread now being seen in the U.S.
The nation recorded 2,242 measles cases in 2025, according to CDC data, linked to 48 separate outbreaks. The CDC reported 245 hospitalizations, mostly in children, and three measles deaths last year. Infections were confirmed in at least 44 states. It was the most cases the country had seen in over three decades.
That record was shattered in 2026, when the U.S. recorded more than double that number of cases by October — a total that topped 5,000 earlier this month.
Almost all of the cases have been in people who were not vaccinated. Measles-related deaths have been reported in Pennsylvania, New York and Wisconsin.
The CDC said 43 new outbreaks — defined as three or more related cases — have been reported so far in 2026, while about a third of the cases reported this year are tied to outbreaks that have been ongoing since 2025.
Who is at risk from measles?
Measles is one of the most contagious infectious diseases. Those who are unvaccinated for the disease are most at risk of getting it. CDC data shows that 96% of people infected with measles in 2026 did not get vaccinated for measles or were unsure of their vaccination status; only 2% of cases were in people who’d been fully vaccinated.
While many people recover, measles can cause severe infections in the lungs and brain that can lead to cognitive issues, deafness or death.
Medical research has shown that two doses of the measles, mumps and rubella (MMR) vaccine is extremely safe and effective at protecting against measles.
Some people — including babies, pregnant women or people with weakened immune systems — cannot get vaccinated for measles, so they rely on population immunity to keep the disease from spreading. Awan said that these groups of people will bear “the brunt of the consequences” of increased measles spread.
“They will be the ones that are most vulnerable to getting infected and experiencing the complications,” such as pneumonia or encephalitis, Awan said.
