Thanks to widespread vaccination, measles was considered “eliminated” as a continuously transmitted disease in the United States since 2000 – but that is no longer the case.
An independent commission of experts reporting to the director of the Pan American Health Organization has determined that the United States is no longer considered to have eliminated measles, a source familiar with the process told CNN on Friday.
The news was first reported by the Wall Street Journal.
The move was widely expected after years of falling vaccination levels and rising case numbers, but it remains a black mark on the country’s public health policy.
The international committee that determines the measles elimination status of countries considers an infection to be endemic or regularly occurring if infections caused by the same strain are transmitted from person to person for at least a year in the same country.
To determine this, committee members examine the genetic code of viruses taken from patients.
Each time a virus copies itself, it makes tiny changes to its genetic code. By studying the genome of different viruses during an outbreak, scientists can determine how closely the infections may be linked and whether they are likely to be part of the same transmission chains.
In August, scientists at the Utah Public Health Laboratory released a preliminary study showing that the same strain of measles had been circulating in the state for more than a year, accounting for more than 95% of cases. It spread from the southwest of the state to central Utah, ultimately causing more than 600 cases between June 2025 and June 2026.
Sustained outbreaks also occurred in South Carolina, Pennsylvania, Wisconsin, and New York, as well as other states.
It’s unclear exactly what data the committee relied on to make its decision, but it wasn’t really a difficult decision, said Dr. Angela Rassmussen, a virologist at the University of Saskatchewan in Canada and editor-in-chief of the journal Vaccine. The Utah data alone would have been enough to justify the decision, she said.
The United States has seen record numbers of measles cases, hospitalizations and deaths over the past two years, even as some members of the Trump administration — including President Donald Trump – have sown doubts about the safety and effectiveness of vaccines that prevent it.
“The elimination of measles is a vital sign for our public health system. It shows cracks in our foundation. Losing elimination status means we are less prepared as a nation to meet the challenges of infectious and noninfectious diseases,” said Dr. Demeter Daskalakis, former director of the National Center for Immunization and Respiratory Diseases at the U.S. Centers for Disease Control and Prevention.
The measles-mumps-rubella (MMR) vaccine is so effective that two doses reduce an exposed person’s chance of getting sick by 97% compared to an unvaccinated person.
Since 2000, when measles was declared eliminated in the United States, the country still experiences a few outbreaks each year. These were caused by sick travelers who brought the virus into the country. Due to community protection maintained through high vaccination rates, these outbreaks were generally small and short-lived.
In 2025 and 2026, However, the virus has affected more unvaccinated families and communities, making them vulnerable to infection.
More than 5,400 cases of measles have been reported in the United States this year – the highest number since 1991. Most are linked to this year’s 43 new outbreaks, but more than 1,000 cases are linked to outbreaks that began last year.
Almost all of this year’s cases involved people who did not receive the MMR vaccine or whose vaccination status is unknown. People have been hospitalized in about 1 in 9 reported cases, according to the CDC, and at least 10 people have died after catching measles, according to state reports.
The statement is a humbling moment for a nation that played a leading role in eliminating smallpox – the world’s only human disease ever eradicated – and worked for decades to drive measles abroad.
“It’s so devastating and so sad that we’re here today,” said Dr. Nuwan Gunawardhana, an infectious disease epidemiologist at Columbia University Irvine Medical Center in New York. “It kind of points in the direction of a real reversal of a generation of progress in public health.”
But it also means that people who are too young to be vaccinated against measles or whose immune function is weakened due to organ transplant, cancer or other illnesses are at higher risk in areas with outbreaks than they were just two years ago.
Most people who get measles recover after having a fever and rash and generally feeling miserable for several days, said Dr. William Moss, a professor and measles expert at the Johns Hopkins Bloomberg School of Public Health. But that doesn’t mean the infection is benign, he added.
Measles can also erase a person’s immune memory. The immune system forgets about infections it previously fought off, leaving the person vulnerable to secondary threats like pneumonia or diarrhea.
If a pregnant woman gets measles, she can pass it to her baby in the womb, and the baby will be born with measles, putting her life at risk.
In rare cases, people who have had measles can develop serious neurological complications, sometimes years after the initial infection. The most serious is subacute sclerosing panencephalitis, or SSPE, which is progressive and fatal.
All these complications can be avoided through vaccination.
The fact that the United States is losing its measles elimination status is “incredibly embarrassing,” said Dr. Peter Hotez, co-director of the Center for Vaccine Development at Texas Children’s Hospital in Houston. But, he says, it signals a bigger message: “Basically, measles is back. »
“Whether or not we’ve officially lost our elimination status is much less important to me than basically measles is here. It’s ubiquitous and vaccination rates are down across the country, and I don’t see us getting back to normal anytime soon,” he added.
Measles is one of the most contagious viruses known to science. A single infected person usually spreads it to 12 to 18 other people. The virus is airborne and can float around a room for hours after a sick person leaves the room.
Soon after the measles vaccine was rolled out in the early 1960s, public health experts realized that if enough people in an area were vaccinated, protection from the vaccine could stop the spread of the virus. The United States set its first goal of eliminating measles transmission in 1978.
Measles is one of 30 diseases that the Pan American Health Organization (PAHO) aims to eliminate by 2030.
In 2016, PAHO and the World Health Organization declared all 35 countries in the Americas region free of continued measles transmission.
That designation was lost last year, however, when Canada’s elimination status ended after a long outbreak that affected several provinces.
Mexico, which has experienced several large measles outbreaks, is also at risk of losing its elimination status.
Moss said that since the United States has lost its measles elimination status, it must be on track to regain it.
“This is not easy, especially in today’s environment of declining public confidence in vaccines, the increase in non-medical exemptions we are seeing in schools, the decline in measles, mumps and rubella vaccination among our kindergarten students and the weakening of vaccine policy,” Moss said.
“So it will not be a trivial task for the United States to regain its measles elimination status. »
Gn Health
