State health officials investigating a case of measles in the state

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Denver (Dec. 20, 2023)–  State health officials have confirmed that an international traveler to Colorado tested positive for measles. The adolescent arrived in Colorado at Denver International Airport on Dec. 13, 2023, and visited several counties. The last confirmed case of measles in a Colorado resident was in January 2019.

Arapahoe County Public Health is leading this disease investigation, alongside the state and several other local public health agencies, in notifying people who may have been directly exposed. The adolescent, whose vaccination status is unknown, has been in isolation since Dec. 18, 2023.

For people who haven’t had the MMR (measles, mumps, rubella) vaccine, measles is a highly contagious and serious infection. The MMR vaccine given within 72 hours after exposure (but before symptoms are present) can prevent infection. Measles can cause complications, such as seizures, brain damage, ear infections, pneumonia, and death.

Vaccination is highly effective against measles, and people who have previously been vaccinated with the MMR vaccine do not need to receive the vaccine again after exposure to measles. Coloradans can check their/their child’s vaccine status through an online database.

Measles is spread through the air and can remain in the air for up to two hours. Signs and symptoms of measles typically begin 7 to 14 days after exposure but may take up to 21 days to appear. A person with measles is contagious for four days before and four days after the rash appears. Signs and symptoms include:

  • Fever, cough, runny nose, and red, watery eyes.
  • Appearance of rash at hairline, spreading downward over body, usually beginning 2-4 days after other symptoms.

The current timeline of the disease investigation is as follows:  

Public health officials believe brief interactions are less likely to lead to infection, but people who were in the following locations should be cautious and monitor for symptoms. 





Denver International Airport

8500 Peña Blvd, Denver, CO 80249

Wednesday, Dec. 13 from 4:30 - 8 p.m.

Possible exposure to people who were moving through Concourse A, bridge security, baggage claim, and passenger pick up area. 

Children’s Hospital Colorado’s Emergency Department at the Anschutz Medical Campus: 13123 E. 16th Ave, Aurora, CO 80045

Monday, Dec. 18 from 8:30 – 11 a.m.

Children’s Hospital Colorado is notifying health care providers, patients, and others who were in a similar area as the measles patient.


What to do if you have signs and symptoms of measles:

If you may have been exposed and are experiencing symptoms, immediately notify your health care provider by telephone. Explain that you may have had a possible measles exposure and describe your symptoms. Call a medical provider before physically showing up to minimize the chance of exposure to other people. If you do not have a health care provider, call an urgent care center or emergency department. For additional information about measles, call the free help line CO-HELP at 303-389-1687 (toll free: 1-877-462-2911).

“Anyone who is experiencing symptoms of measles should stay home unless they need medical treatment,” said Dr. Rachel Herlihy, Colorado State Epidemiologist. “People with signs and symptoms of measles should also not go to child care facilities, school, work, or other public places to avoid exposing others to this very serious and highly contagious disease.”


The MMR vaccine is safe and effective at preventing measles (as well as mumps and rubella). Two doses of MMR are approximately 97% effective at preventing measles infection. 

Centers for Disease Control and Prevention recommends children receive a first dose of MMR vaccine at 12 to 15 months of age and a second dose at 4 to 6 years of age. People who receive MMR vaccination according to the U.S. vaccination schedule are usually considered protected for life against measles.

The vaccine is widely available in Colorado at no or low cost. The federal Vaccines for Children program provides vaccines at no cost for children from birth through 18 years who are uninsured, underinsured, on Medicaid or Medicaid eligible, and/or Alaskan Native/American Indian.