US could lose its measles elimination status within months, experts say
The United States could lose its measles elimination status as early as January, marking the lasting resurgence of a disease that was eliminated from the country 25 years ago.
On November 10, Canada has lost its measles elimination statusafter the Pan American Health Organization concluded that recent measles outbreaks in the country were linked and represented continuous transmission lasting more than 12 months. Measles is considered eliminated in a country or region only when there has been no outbreak for more than a year. Thus, to maintain “elimination status,” any introduction of the disease during travel must be canceled before 12 consecutive months of spread.
A large measles outbreak in West Texas began in January 2025 and has since ended — but even as it raged, it may have sparked cases in Arizona and Utah, where ongoing outbreaks still occur. If public health officials find enough evidence linking these outbreaks, the U.S. see its measles elimination status disappear in January 2026.
“We still don’t know how the determination will take place in January,” said Dr Diego Hijanoinfectious disease specialist at St. Jude Children Research Hospital. “But it’s likely, looking at cases that started in Texas and continued to spread, that they will think there were 12 months of cases coming from that area.”
Measles elimination is a valuable public health goal. The illness, marked by a high fever and a dramatic red rash, is miserable at first, but it can also lead to life-threatening complications, including pneumonia and swelling of the brain. According to the Centers for Disease Control and Prevention (CDC), 1 to 3 out of 1,000 children who get measles die during this acute phase of infection.
For survivors, measles can cause long-term health consequencesincluding immune “amnesia” that makes them prone to other illnesses. And about 7 to 11 survivors out of every 100,000 infected people face a deadly long-term complication called subacute sclerosing panencephalitis, a degenerative disease of the nervous system that occurs years after measles infection.
Two doses of the measles, mumps and rubella (MMR) vaccine reduce the risk of getting measles by 97%, according to the American Academy of Pediatrics. As measles is one of the most communicable infectious diseases in the world, its elimination requires high levels of vaccination. In a population without immunity, a person with measles can infect between 12 and 18 others. To quell an outbreak, you need to get that number below 1, meaning that about 95% of the population needs to be protected by vaccination or immunity from previous infection, Hijano told Live Science.
Nationally, 92.5% of kindergartners are up to date on their MMR vaccinations, According to the CDC data from the 2024-2025 school year. This number is even lower in some regions and communities, such as the predominantly Mennonite community of West Texas. These low vaccination coverage groups not only represent people at risk of personally catching measles, but also pose a challenge to public health responders trying to contain outbreaks, said Amy Winterdemographer and infectious disease epidemiology researcher at the University of Georgia.
“It’s much more difficult in terms of personnel going out and doing investigations,” Winter told Live Science. Because large numbers of people are susceptible in these communities, public health officials may have more difficulty listing an infected person’s contacts and encouraging them to self-isolate or receive a post-exposure vaccine, which may prevent or reduce the severity of measles infection.
“If you can’t stop a chain of transmission within 12 months,” Winter said, “that really indicates that we don’t have control over this pathogen.”
The United States experienced 45 measles outbreaks and 1,723 confirmed cases in 2025, according to CDC data covering until November 12. To determine whether any of these outbreaks are related, indicating continued transmission, public health officials are investigating each case, looking for times and places where infected people may have overlapped with others who caught the disease.
They also conduct genetic testing to determine whether the measles strains causing the cases are related or whether the infection came from a separate introduction. Most travel-related cases occur when a susceptible U.S. resident travels abroad to an area where measles is prevalent. endemicWinter said.
This week, public health officials said on a call between federal and state agencies that the outbreaks in West Texas were linked to ongoing outbreaks in Utah and Arizona. The New York Times reported. If these results are confirmed, the United States will lose its status in January unless the outbreaks in Arizona and Utah end with no new transmission.
Of confirmed cases in the U.S. so far this year, 92% have been in unvaccinated people and another 4% have been in people who have only received their first dose of MMR. The recommended dosing regimen for MMR is to receive the first dose at age 1 year and the second between ages 4 and 6 years. To get measles under control again, Hijano said, the United States will need to increase its nationwide vaccination rate above 95%.
“Until we have such a high vaccination rate,” he said, “there will always be cases of measles coming from another country or another region that will find a place to spread.”
This article is for informational purposes only and is not intended to offer medical advice.
