The Public Health Seattle and King County said in a statement published on May 31 that the traveler passed through the busy travel hub on May 10 and May 11 “while infectious.”
The agency noted that the person “was likely exposed to measles” while traveling to or around Europe. They did not include details on where in Europe they traveled.
The person’s vaccine status is also unknown.
People who were at the following locations and times might be at risk of developing measles within 21 days from the exposure date, according to public health officials.
Between 5:30 p.m. and 9:30 p.m. on Friday, May 10, the carrier used the S Concourse (Gate S1) and passed through Customs to International Arrivals Facility Baggage Claim (Carousel 19).
The next morning, Saturday, May 11, the infected person was at the A Concourse (Gate A8) between 7:30 a.m. and 11:30 a.m., health officials said.
If you were at the locations at the times listed above and are not immune to measles, the most likely time you would become sick would be between May 17 and June 1, according to health officials, who noted immuno-compromised people may take longer to experience symptoms.
The virus can remain in the air for up to two hours after someone infectious with measles leaves the area.
“Measles is highly contagious and if you don’t have immunity, you can get it just by being in a room where a person with measles has been,” said Dr. Eric Chow, Communicable Disease Chief for Public Health—Seattle & King County.
According to the U.S. Centers for Disease Control and Prevention (CDC), measles is a highly transmissible virus that mainly spreads after a carrier coughs or sneezes.
The agency said symptoms such as rash, high fever, cough, red and watery eyes, and a runny nose generally appear within seven to 14 days of contact with the virus.
“Small raised bumps may also appear on top of the flat red spots,” and the “spots may become joined together as they spread from the head to the rest of the body,” the CDC says. “When the rash appears, a person’s fever may spike to more than 104 degrees Fahrenheit.”
Measles Cases in 2024 Double 2023 Total
The alert at Seattle’s busy international airport comes as the CDC published data on May 30 showing the total number of measles cases in the United States so far this year has more than doubled the annual total of 58 in 2023.
The agency said in a report that 146 measles cases were reported in 21 jurisdictions in the United States as of May 30, along with 11 outbreaks.
The CDC defines an outbreak as three or more related cases.
The surge in cases comes after multiple outbreaks of the contagious virus were reported in several areas across the United States, including a Chicago shelter holding illegal immigrants.
In a statement on May 16, the CDC said 57 cases were associated with residence in or contact with persons in the shelter—just one case less than the total number of measles cases in the United States for the entirety of 2023.
Health officials said a coordinated and prompt response with “a high-coverage mass vaccination campaign” reduced the size and duration of the outbreak.
Meanwhile, the CDC issued an alert in March that international travelers should be wary of the surge in cases in the United States and worldwide, advising travelers to get the measles vaccine. It namely singled out countries including the United Kingdom, Austria, Romania, and the Philippines as ones that are experiencing measles outbreaks.
The CDC also advised parents who plan to travel outside the United States to speak with a health care provider to make sure they received the MMR vaccine at least two weeks prior.