Colorado records 36th measles case of the year, state’s epidemiologist says vaccination provides the best protection

Colorado recorded three new measles cases on Monday, bringing the total for the year to 36, far surpassing totals from previous years.

They come as the nation has seen a dramatic increase in cases. For the first time in a quarter century, the U.S. could lose its measles-free status.

One case was in a Weld County resident, a school-aged child who had not received the measles, mumps, and rubella, or MMR, vaccine, according to the Colorado Department of Public Health and Environment and the Weld County Department of Public Health and Environment. It's the first case reported in that county this year.

Those agencies, in a statement, said the child developed measles symptoms after traveling to part of another state where there is an ongoing measles outbreak. They say there are no known public exposure locations associated with the case.

Two new cases have also been confirmed in residents of Montezuma County in southwest Colorado. They are unvaccinated household contacts of a previously confirmed case. Both have been in quarantine during their infectious period, so there are no known public exposure locations associated with the cases. That’s according to the state health department and Montezuma County Public Health Department.

“With the holiday season in full swing, getting vaccinated is the best way to protect yourself, your family, and your community from measles,” said Dr. Rachel Herlihy, Deputy Chief Medical Officer and State Epidemiologist, in a statement.

She noted that holiday gatherings often involve close contact indoors and travel to see family and friends; that creates an environment where measles can spread easily.

“Ensuring you are up to date on the MMR vaccine is critical to protecting vulnerable loved ones you may visit, including infants too young to be vaccinated and family members with weakened immune systems,” Herlihy said.

Of Colorado’s 36 cases in 2025, the vast majority, 28, came in those who were unvaccinated or who have unknown vaccine status. Since 2014, the state has only recorded zero cases or one case each year, except in 2016 when it had two.

Cases have now been identified in 10 of the state’s 64 counties, from all over the state. Mesa County has recorded the most cases to date, with 11, that’s according to the state health department website.

Five people have been hospitalized this year; none has died.

Measles has also hit the United States hard. As of Dec. 9, 2025, a total of 1,912 confirmed measles cases were reported in the country, according to the CDC. There have been 47 outbreaks reported in 2025, with 88 percent of cases being outbreak-associated.

People were hospitalized in 11 percent of cases; three people have died from measles in the U.S. this year.

People exposed to measles generally develop symptoms between a week to 21 days following exposure.

If you get symptoms, immediately contact your health care provider by phone, the state health department said in a press release.

If you do not have a provider, call an urgent care center or emergency department and explain that you may have been exposed to the virus. Calling ahead helps prevent additional exposures, health officials said.

For more information, you can check the state’s measles webpage. It includes information about symptoms, transmission, and vaccine recommendations, 2025 Colorado measles case information, and a current list of exposure locations.