A traveler who passed through Seattle-Tacoma International Airport on Thursday has been confirmed with measles, according to health officials. The person moved through the airport's A Concourse, passed through the international arrivals hall and baggage claim, then exited on the lower level of the main terminal. People who are not immune could still develop symptoms in the days and weeks after exposure, and officials are urging anyone unsure about their vaccination status to check their records.
Public health officials outline the case
Public Health - Seattle & King County says the confirmed case involves a Canadian resident who traveled through Sea-Tac on Jan. 22 and is no longer in King County. According to Public Health - Seattle & King County, measles can spread before symptoms or a rash appear, which is why officials have posted potential exposure locations. "We are at a pivotal moment with more measles outbreaks happening throughout the U.S. and abroad," the county health officer said on the county blog.
Where exposures may have occurred at Sea-Tac
Local reporting lists the traveler as being in A Concourse near Gate A12, passing through the International Arrivals Hall at baggage claim 22, and leaving on the lower-level south baggage claim between 4 p.m. and 7 p.m. on Jan. 22. Those details were outlined by KOMO News, which notes that anyone who was in those spots and is not immune should watch for symptoms through mid-February.
When symptoms might appear
Public health guidance says that anyone exposed who does not have immunity would most likely develop symptoms between Jan. 29 and Feb. 12, although incubation can last longer for people with weakened immune systems. Officials urge people who think they were exposed to call a health care provider before visiting a clinic or hospital and to limit contact with others while they wait for guidance, per Public Health - Seattle & King County.
Statewide status and the Snohomish outbreak
The Washington State Department of Health measles dashboard lists eight confirmed measles cases in the state so far in 2026 and points to county-level exposure maps and advisories. State health officials have urged vaccination and are tracking exposure locations as the situation develops, while local public health agencies continue to update lists of potential exposure sites.
How to protect yourself
Two doses of the MMR vaccine are about 97% effective at preventing measles, according to the Centers for Disease Control and Prevention, and vaccination remains the most reliable defense. The Snohomish County Health Department reports that it has confirmed additional cases, bringing the county total to six, and notes that children under 19 in Washington can be vaccinated for free. The county also recommends that unimmunized people born after 1956 quarantine for 21 days after a known exposure.
Where to find updates
For the full list of potential exposure locations and the state's interactive map, readers can visit the Washington State Department of Health measles page. Local updates and the latest Sea-Tac details are available through local reporting and county releases, including coverage by KOMO News.
