It’s been a full year since one of the worst measles outbreaks in recent U.S. history struck West Texas. The highly contagious disease continues to spread across several US states, Mexico and Canada after an outbreak was reported among children in Texas in January 2025. The U.S. was free of the disease for more than a quarter-century thanks to highly effective and safe vaccines, but now experts say we are on track to lose that status if officials determine that measles has been spreading continuously for a year.
“The United States is in the grip of the deadliest measles outbreak seen in decades,” says Jennifer Nuzzo, an epidemiologist and director of the Epidemic Center at Brown University. “Losing measles elimination status is an official acknowledgment that the country is on the wrong track.”
For measles, the Pan American Health Organization (PAHO) formally declares that a country has “eliminated” the disease when cases cannot be linked to each other – there is zero sustained transmission for 12 months or more. The US officially lost its eradication status last November when PAHO’s review of epidemiological data showed that Canada was no longer measles-free for a year.
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“The loss of measles elimination status does not entail a formal ban, but it is an important public health signal,” a PAHO spokesperson wrote in an e-mail. scientific American. “Elimination is recoverable. The US has faced setbacks before – including temporary loss of status in Venezuela (2018) and Brazil (2019) – and has successfully achieved eradication through intensive vaccination, robust surveillance, and rapid outbreak response.”
PAHO said its group that reviews the status of measles elimination in the US and Mexico expects to meet again one year after the initial outbreak in West Texas. Its spokesperson said the organization would hold its meeting on April 13 to give countries enough time to provide documents and data. Epidemiologist Walter Orenstein, who sits on a committee of the Task Force for Global Health, which independently reviews the elimination of diseases, expects the US to soon follow Canada.
“It definitely feels like we have lost our status, but we have to look at the data,” he says, adding that a task force for the Global Health Committee has not been convened at this stage to look at the current situation.
The United States has maintained its status of measles elimination since the spread of the virus was stopped in 2000.
“Elimination in itself is a huge public health achievement – but especially with measles because the virus is so contagious,” says virologist Angela Rasmussen of the University of Saskatchewan.
A very high level of population immunity is required to prevent measles from spreading; At least 95 percent of people in a community must be immune from prior infection or vaccination. And national vaccination effort “It has played a central role in increasing the level of population immunity in the United States,” says Orenstein, professor emeritus at Emory University, who has worked on measles eradication for decades. The recommended two doses of measles, mumps and rubella (MMR) vaccine is typically 97 percent effective in preventing the disease for life. “This interference can stop and break the chain of transmission,” he says.
Before the MMR vaccine became available in 1963, measles caused an average of four million cases, 48,000 hospitalizations, and 400 to 500 deaths per year in the United States. Orenstein says most people know measles for its itchy rash, but it can also cause high fever, ear infections, severe dehydration, pneumonia and chronic brain inflammation or encephalitis.
Such severe cases of measles – which had not been seen on a large scale in US hospitals for decades – resurfaced during recent outbreaks.
The first major outbreak was recorded on January 20, 2025, in an under-vaccinated community in Gaines County, West Texas. From there, “cases increased rapidly,” says Katherine Wells, public health director for the city of Lubbock, Texas, about 70 miles away in Gaines County. “We saw 99 individuals require hospitalization, meaning either their oxygen levels got too low, they got pneumonia or they were so dehydrated they had to be given IV fluids,” Wells says. “Two young children lost their lives due to measles, and this is unprecedented. Since we have a measles elimination situation, we have not seen any deaths.”
In 2025, the CDC recorded outbreaks in 24 states and confirmed 2,144 cases.Highest total since 1991. The majority of infections were in children, with 69 percent of those occurring in people 19 years of age and younger. of them casesOne adult and two children died; All three were not vaccinated.
State officials declared an end to the West Texas outbreak in August 2025, but outbreaks in other states continue to grow; In recent months, infections have been reported in South Carolina reached 434While Arizona has 223 cases registeredand utah has 201 cases registered. It remains to be seen whether these outbreaks originated from the initial epicenter in western Texas.
“If (health officials) make this connection, there will be a whole year of transmission, and we will almost certainly lose measles elimination status,” Wells says.
Previously, cases of measles occurred sporadically in people who traveled to countries where the disease was more prevalent, but those small outbreaks were quickly contained and never lasted more than a year. Rasmussen says the main reason measles has spread to such an extent now is due to declining national vaccination rates and an increase in antivaccine messaging driven by Health and Human Services Secretary Robert F. Kennedy, Jr. in response to scientific American, A spokesperson for the Department of Health and Human Services said vaccination is the most effective way to prevent measles. But the secretary repeatedly said Its security was underestimated for the media During the outbreak.
“When there was an outbreak in Texas, it took even Kennedy a long time to say that the vaccine was the only way to prevent measles,” says Rasmussen. “He has gone out of his way to promote alternative treatments that are unproven to work, such as vitamin A, cod liver oil, and steroids.”
Wells says local public health workers and health care workers tried to mobilize quickly to provide care and vaccines to children and community members, but Trump administration budget cuts, layoffs and restructuring of US health agencies disrupted support for their response efforts. “Some of our federal partners in the public health outbreak were not necessarily available to us,” she says.
News outlets have recently reported U.S. federal officials are trying to prove that ongoing infections in Utah, Arizona and South Carolina are not linked to the cases in West Texas to prove the country is still measles-free. Health officials conduct epidemiological investigations to trace infections to common sources, as well as genomic testing to compare viruses isolated from different outbreaks. But the purpose of this type of public health testing is to help prevent transmission and provide support to vulnerable groups with low vaccination rates — not to preserve a public health ticket, Nuzzo says.
“It’s important to understand whether these cases are linked because it can help inform efforts to control the spread of measles,” Nuzzo says, “but we shouldn’t be looking for this information like we’re trying to get out of an embarrassing political situation.”
are responding science, An HHS spokesperson did not comment on the news reports and wrote in an e-mail on January 15 that the US had not met the threshold for losing eradication status.
The resurgence of measles in the US ultimately means cases will become common — and communities will face regular, sometimes deadly, outbreaks. Those outbreaks are also incredibly expensive. An analysis last October Nuzzo says it’s estimated that the average health care cost per case of measles in the U.S. was $43,000 — far more expensive than vaccination. He, Rasmussen and Orenstein fear that other historic, vaccine-preventable diseases like polio could also return.
Even if it is proven that the current outbreaks are not related to the one that began in January 2025, Wells says it is only a matter of time before measles is no longer considered eliminated in the US.
“Unless we change the trajectory of vaccine uptake in our communities, we will lose our status at some point,” she says. “The status of elimination is just a technical thing. The real concern is that we are seeing transmission of measles in communities, and we have an effective way to prevent that from happening.”
