First measles case of the year confirmed in Southern Colorado, health officials say (2025)

The first case of measlesof the year in Colorado was announced Monday after health officials say an unvaccinated adult recently traveled to an area of Mexico that's currently experiencing an outbreak.

The Colorado Department of Public Health and Environment and the Pueblo Department of Public Health and Environment said Monday evening that the case was confirmed in the Southern Colorado town of Pueblo.

The departments are urging people who were in or near Southwest Deli and Cafo between March 17 and March 20 or the Southern Colorado Clinic on March 22 to monitor for symptoms.

Health officials say symptoms typically develop between 7 and 21 days after exposure. Between 7 and 14 days, those symptoms can include fever around or over 104°, cough, runny nose, and red, watery eyes. Within 2 to 3 days after those symptoms appear, small white spots may appear in one's mouth and days later, a full rash can appear.

Most people's symptoms will improve, but about 1 in 5 unvaccinated people who get measles will be hospitalized. Approximately 1 in every 1,000 children with measles will develop brain swelling that can lead to brain damage, and around 3 in 1,000 children who become infected will die, the U.S. Centers for Disease Control and Prevention says.

"Measles is one of the most contagious diseases we know, but it is also highly preventable," Dr. Rachel Herlihy, deputy chief medical officer and state epidemiologist, said in a statement. "The MMR vaccine provides excellent protection and helps prevent outbreaks like the one we are seeing globally. We urge Coloradans to review their vaccination status and take steps to protect themselves, their families, and their communities."

This month, the U.S. recorded the mostmeasles casesin a single year since 2019, CDC data shows. The majority of infections have been reported in West Texas, andone child has died of the disease, local health officials said. Texas has seen400 casesand the rest of the country has seen 483 recorded cases this year so far. And Kansas, to Colorado's east, has reported over 20 cases so farthis year.

The majority of people reporting cases are 19 or younger. CDC data shows the following age breakdown of cases:

• Under 5 years: 157 (33%)
• 5-19 years: 204 (42%)
• 20+ years: 111 (23%)
• Age unknown: 11 (2%)

The overwhelming majority of cases, the CDC says, are also among those who aren't vaccinated for measles or whose vaccination status isn't known:

• Unvaccinated or Unknown: 97%
• One MMR dose: 1%
• Two MMR doses: 2%

The number of measles cases in the U.S. has fallen dramatically since the advent of the vaccine in 1963. Prior to that, the country typically saw hundreds of thousands of cases each year.

Health experts point tolower vaccination ratesas a reason for increases inpreventable diseaseslike measles.

More information on measles can be found on the Centers for Disease Control and Prevention's website.