Seattle health officials advise SEA airport visitors to check immunity after measles case

SEATTLE — Public Health – Seattle & King County has reported a measles case involving an out-of-state traveler who passed through Seattle-Tacoma International Airport (SEA) on Nov. 11 and Nov. 17.

The person’s vaccination status remains unknown.

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Health officials are urging anyone who was at the airport on those dates and is unsure of their immunity to visit the Public Health website for detailed exposure information.

This case marks the fifth instance this year of measles in travelers passing through King County who are not Washington residents.

Additionally, there have been 12 measles cases among Washington state residents in 2025.

Measles is highly contagious and can spread before symptoms, such as a rash, appear. The virus can linger in the air for up to two hours after an infected person leaves an area. Public Health advises that those potentially exposed should verify their vaccination status and contact a healthcare provider if they develop a fever or unexplained rash.

It is crucial to call ahead before visiting a clinic to prevent further spread.

The likely symptom onset for those exposed on Nov. 11 is between Nov. 18 and Dec. 2, while exposure on Nov. 17 may lead to symptoms from Nov. 24 to Dec. 8. Immuno-compromised individuals may experience delayed symptom onset.

Measles can lead to severe complications, including pneumonia and encephalitis, particularly in high-risk groups such as young children, pregnant individuals, and those with weakened immune systems. The disease is preventable through the MMR vaccine, which is about 97% effective with two doses.

For more information on measles, vaccination, and exposure details, visit the King County measles webpage.