A measles outbreak in Arizona and Utah shows no sign of slowing, putting the United States dangerously close to losing its elimination status for the vaccine-preventable disease.
With holiday travel and gatherings approaching, doctors worry that transmission could escalate. If measles continues to spread through Jan. 20, that will mark a year of sustained transmission in the United States. At that point, the disease would no longer be considered eliminated and it would instead revert to being endemic, or constantly present.
The backward step seems highly likely.
“These pockets of communities that have low vaccination rates — if we’re not able to get them vaccinated before the holidays, we are very much at risk of going into 2026 and losing U.S. measles elimination status,” said Dr. Rebecca Sunenshine, medical director of the Health Observatory at Arizona State University.
Canada lost its measles elimination status this month, having recorded more than 5,000 cases since October 2024.
In the last few weeks, Utah has reported 18 new measles cases. Most of the state’s 87 cases this year have been in Washington County, which borders Arizona.
Exposures have been reported at emergency departments and urgent care clinics in the county, as well as in Salt Lake County. Several exposures were reported at Water Canyon Elementary School in Hildale, which is just across the border from Mohave County, Arizona, where all but four of the state’s 137 cases this year have been recorded.
During the 2024-25 school year, just 78% of kindergartners in Mohave County had received the recommended two doses of the measles, mumps and rubella (MMR) vaccine.
“Unfortunately, it hit a community where a lot of folks are unvaccinated, and that’s why it spread so quickly,” Sunenshine said.
To curb the spread of measles, a vaccination rate of at least 95% is needed. Nationally for the 2023-24 school year, less than 93% of kindergartners had received two doses of the MMR vaccine.
Public health experts attribute the high U.S. case total this year to declining vaccination rates. The vast majority of the infections have been in people who are unvaccinated or have unknown vaccination statuses.
A large proportion of the cases this year (762) came from an outbreak in West Texas in which two unvaccinated children died. The outbreak stretched into New Mexico, as well, where an unvaccinated adult died. Texas declared the outbreak over in August.
The CDC’s acting director, Jim O’Neill, said Tuesday on X that the Utah and Arizona cases are not directly linked to the Texas outbreak, based on a preliminary analysis.
The agency did not respond to questions about the possibility that the United States could lose its elimination status or how the CDC is responding to the current outbreak. A CDC media officer directed NBC News to O’Neill’s statement on X: “@CDCgov continues to work with state and local health agencies to assess transmission patterns and ensure the same effective public health response that led to the Texas outbreak being declared over.”
Measles is highly contagious. If they are not immune, up to 90% of people in close contact with an infected person will get sick. The virus can linger in the air for up to two hours.
The illness is particularly dangerous for babies and young children. Symptoms include a characteristic blotchy rash, as well as high fever, cough, runny nose, pink or watery eyes and white spots on the insides of the cheeks. Severe cases can progress to pneumonia or swelling of the brain.
Measles cases are also climbing in South Carolina, with all but three of the state’s 52 cases this year connected to an outbreak in Spartanburg County. The outbreak initially centered on two schools, but the state has identified some cases without known sources of transmission, indicating ongoing community spread.
“This is the first significant outbreak that we’ve had in many, many, many, many years,” said Dr. Stephen Thacker, an associate professor of pediatrics at the Medical University of South Carolina. “We’ve done a lot of testing to make sure that we’re not missing the opportunity to make diagnoses early.”
Thacker said that although the first MMR vaccine dose is given at 1 year of age, parents who have children under 12 months and who live in areas with measles outbreaks — or are traveling to one over the holidays — can consult doctors about whether to start the series early for their children.
“At times of high travel and during cold months, where we gather inside more frequently, these are times where we know respiratory viruses spread amongst families and certainly amongst communities,” he said.
Under the leadership of Health Secretary Robert F. Kennedy Jr., the CDC has been criticized by some public health experts for not strongly emphasizing the importance of measles vaccination. Kennedy, who co-founded an anti-vaccine nonprofit group, has called for people to get the MMR vaccine but has framed it as a personal choice while at the same time emphasizing unproven treatments such as steroids and antibiotics. He also falsely claimed that immunity from measles vaccines wanes quickly.
Sunenshine said the most important messaging about vaccines comes from local health care providers, rather than federal officials.
“People rely the most on what they hear from their own personal physicians and the nurses,” she said.
