A Measles outbreak in Arizona and Utah is showing no signs of slowing down, putting the United States dangerously close to losing vaccine-preventable disease elimination status.
With holidays and gatherings approaching, doctors fear transmission of the virus could worsen. If measles continues to spread through January 20, it will mark a year of sustained transmission in the United States. At this point, the disease will no longer be considered eradicated and will instead become endemic or ever-present again.
A step back seems very likely.
“These groups of communities with low vaccination rates — if we can't get them vaccinated before the holidays, we are at great risk of entering 2026 and losing measles elimination status in the United States,” said Dr. Rebecca Sunenshine, medical director of the Health Care Observatory at Arizona State University.
Canada lost the status of eliminated measles this month, more than 5,000 cases have been reported since October 2024.
Over the past few weeks, Utah 18 new cases of measles recorded. Most of the 87 cases this year have occurred in Washington County, which borders Arizona.
Cases have been reported in emergency rooms and urgent care clinics throughout the county, as well as in Salt Lake County. Several cases have been 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 students are being held. 137 cases this year were recorded.
Total for the 2024-25 academic year 78% of child care centers in Mohave County have received the recommended two doses of measles, mumps, and rubella (MMR) vaccine.
“Unfortunately, it hit a community where a lot of people are not vaccinated, and that's why it spread so quickly,” Sunenshine said.
To curb the spread of measles, vaccination rates must be at least 95% necessary. Nationally for the 2023-24 school year less than 93% of kindergarteners received two doses of the MMR vaccine.
Public health experts attribute the high infection rate in the U.S. this year to declining vaccination rates. The vast majority of infections occurred in people who were not vaccinated or had unknown vaccination status.
Most of this year's cases (762) stemmed from an outbreak in West Texas that resulted in the deaths of two unvaccinated children. The outbreak has spread to New Mexico, where an unvaccinated adult died. Texas declared an end to the outbreak in August.
Acting CDC Director Jim O'Neill said on Tuesday on X The cases in Utah and Arizona are not directly linked to the outbreak in Texas, according to preliminary analysis.
The agency did not respond to questions about the possibility that the United States could lose eradication 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 declaration of the end of the outbreak in Texas.”
Measles is highly contagious. If they do not have immunity, up to 90% of people who are in close contact with an infected person will become ill. The virus can survive in the air for up to two hours.
The disease is especially dangerous for infants and young children. Symptoms include a characteristic blotchy rash, as well as a high fever, cough, runny nose, pink or watery eyes and white patches on the inside of the cheeks. In severe cases, pneumonia or swelling of the brain may develop.
Measles cases are also rising in South Carolina, with all but three of the state's 52 cases this year linked to outbreak in Spartanburg County. The outbreak initially occurred in two schools, but some cases with no known sources of transmission have been identified in the state, indicating continued community spread.
“This is the first significant outbreak we've had in many, many, many, many years,” said Dr. Steven Tucker, assistant professor of pediatrics at the Medical University of South Carolina. “We did a lot of testing to make sure we weren’t missing the opportunity to make an early diagnosis.”
Tucker said that while the first dose of the MMR vaccine is given at age 1, parents who have children under 12 months of age and live in areas with measles outbreaks (or travel there for the holidays) may want to consult with doctors about whether to start vaccinating their children earlier.
“During long trips and during the colder months when we gather indoors more often, we know that respiratory viruses spread among families and certainly among communities,” he said.
The Centers for Disease Control and Prevention (CDC), under the leadership of Secretary of Health Robert F. Kennedy Jr., has been criticized by some public health experts for not emphasizing the importance of measles vaccination. Kennedy, who co-founded an anti-vaccine nonprofit, urged people to get the MMR vaccine but framed it as a personal choice while also emphasis on unproven treatments such as steroids and antibiotics. He also falsely claimed that immunity from measles vaccine wanes quickly.
Sunenshine said the most important messages about vaccines are coming from local health care providers, not federal officials.
“People rely most heavily on what they hear from their personal doctors and nurses,” she said.
