Denver – Health officials are tracking potential measles exposures stemming from an out-of-state traveler who passed through Denver International Airport (DIA) and a location in Littleton, Colorado, earlier this week. The Colorado Department of Public Health and Environment (CDPHE) issued a public health alert on February 26, 2026, urging individuals to review their immunization records and be vigilant for symptoms.
The traveler, whose origin and specific travel dates have not been disclosed, was confirmed to have measles. Exposure locations include DIA and an unspecified site in Littleton. Arapahoe County Public Health is assisting CDPHE in the investigation, focusing on identifying and notifying individuals who may have been exposed.
This incident occurs against a backdrop of increasing measles cases in the United States. According to the Centers for Disease Control and Prevention (CDC), measles is a highly contagious, vaccine-preventable disease. A report published by the CDC on January 29, 2026, detailed a measles outbreak in Colorado during May and June of 2025, linked to an international traveler. That outbreak involved nine secondary cases and one tertiary case, with four patients requiring hospitalization. The CDC report noted that even vaccinated individuals can, in rare instances, test positive for the virus, though typically only in urine samples, not in respiratory specimens.
CDPHE emphasizes that two doses of the measles, mumps, and rubella (MMR) vaccine are 97% effective in preventing measles. Health officials are urging all eligible individuals to ensure they are fully vaccinated. The current alert specifically advises anyone who may have been exposed at DIA or the Littleton location to monitor for symptoms, which include fever, cough, runny nose, and a rash that typically begins on the face and spreads downward.
The investigation is complicated by the potential for asymptomatic transmission. The CDC report from January highlighted instances where the virus was detected in urine samples of vaccinated individuals, suggesting the possibility of undetected spread. CDPHE has not yet indicated whether urine testing will be incorporated into the current investigation.
As of February 27, 2026, CDPHE has not released details regarding the number of potential exposures or the specific timeframe of the traveler’s presence in Colorado. The department stated that it is working to identify and contact potentially exposed individuals, but declined to provide further information, citing the ongoing nature of the investigation.
