A third case of measles was confirmed and linked to Broomfield High School on Wednesday. In response, state public health officials officially classified the situation in Broomfield as a measles outbreak, which the federal Centers for Disease Control and Prevention defines as three or more related cases.
The new case is the state's fourth this year, giving Colorado a bad start when it comes to measles for 2026. It recorded 36 cases last year, which was the most the state had seen in years, as measles spread widely nationally.
It was confirmed in an unvaccinated child in Adams County, according to the Colorado Department of Public Health and Environment and Adams County Health Department. They're a known contact of another case tied to Broomfield High, where two unvaccinated students have contracted measles.
Health officials posted two locations in Broomfield where possible exposures may have happened: Broomfield Heights Middle School on Feb. 17-19; and Broomfield Community Center on Feb. 19. Measles is a highly contagious but preventable disease, with the measles, mumps, and rubella or MMR vaccine. Details of possible exposure locations are listed on the state health department website.
Students and staff who may need to take additional health precautions will be contacted directly by local public health officials and school administrators. Other exposures for this individual are under investigation.
Outbreaks last year
Colorado had three measles outbreaks in 2025:
- An outbreak in Mesa County, which began in August and involved 11 cases.
- An outbreak in May and June that involved 10 Colorado cases (as well as cases in other states) connected to an out-of-state traveler who flew while infectious.
- Two cases among non-Colorado residents who were likely exposed in the Pagosa Springs area
Measles is one of the world’s most contagious diseases. It’s spread by contact with an infected person, via coughing or sneezing, or breathing the air that was breathed by someone with measles.
The virus remains active and contagious in the air or on infected surfaces for up to two hours.
That means that one person infected by measles can generate up to 18 secondary infections. In other words, one infected person can spread it to 18 other people, according to the World Health Organization.
Public health officials urge getting the measles, mumps, and rubella (MMR) vaccine as the best way to protect you, your family, and your community.
Measles often starts with a fever, cough, runny nose and red eyes. Then it can develop a rash, which begins on the face and spreads down the body. About 30% of all cases will result in complications, most commonly seen in children younger than 5 years and adults. Approximately one in 1,000 people infected with measles will die, according to the American Academy of Pediatrics.
If you have not had the MMR (measles, mumps and rubella) vaccine, you can still get it within 72 hours of exposure to help prevent illness, according to the state health department. In some exposure cases, immunoglobulin (an antibody) given within six days may also help prevent or lessen illness.
Preventing spread
Anyone who was in the locations at the listed dates and times may have been exposed, according to the health department. Watch for symptoms for 21 days after exposure.
Call the state health department (720-653-3369) or your local public health agency right away if symptoms develop, the agency said in its release. “If you need medical care, do not delay. Call your health care provider, urgent care, or emergency department before going in, and tell them you may have been exposed to measles,” it said.
This helps prevent further spread.
Monitoring for symptoms, the agency said, is key for those who have not been vaccinated with the MMR vaccine, particularly infants under 1 year who are not routinely recommended for the vaccine
According to a press release, the state will add any new exposure locations to the CDPHE exposures webpage as they are identified.
Additional information
Visit the CDPHE measles webpage, which includes information about symptoms, transmission, and vaccine recommendations, 2026 Colorado measles case information, and a current list of exposure locations.
