Health officials are sounding the alarm over a potential measles exposure at Seattle-Tacoma International Airport.

An infected infant visited the airport’s S Concourse with their family, potentially exposing others to the world’s most infectious disease.

The person was at the airport – the largest in the Pacific North West, and one of the busiest in America – on April 17 between 4:50pm to 7:45pm.

The individual also passed through the customs and baggage claim areas before exiting through the south end of main terminal.

They later visited Seattle Children’s Emergency Department after developing symptoms on April 17, 18 and 20, and they were admitted on April 20. Their condition remains unknown. 

Officials are warning anyone who fears they may have been exposed to contact their health provider and monitor for symptoms in what is the latest in a string of measles scares to rock America’s major airports.

It marks the fifth case of measles in Washington state this year, three of which have been infants. 

In the past month, New Jersey’s Newark Liberty International Airport and John F. Kennedy airport along with hubs in Washington DC and Los Angeles were all plunged into chaos over measles alerts.

It comes amid a major outbreak in West Texas, that has already sickened around 500 people and led to two deaths, marking the first fatalities in a decade in the US.

Nationwide, cases crossed a grim milestone last month surpassing the tally for the whole of 2024 and reaching their highest level since 2019.

Health officials suspect the latest patient was exposed to measles while traveling abroad. They had not yet been vaccinated.

Officials are warning anyone who may have been exposed to the virus to monitor themselves for symptoms for the next two weeks, particularly if they are unvaccinated, and contact their health provider.

Anyone who develops symptoms is encouraged to immediately contact health services for treatment.

Seattle–Tacoma International Airport is the primary international airport serving Seattle and its surrounding metropolitan area.  

In 2024, it served 52.6 million passengers, ranking 11th in the US by passenger numbers. 

Officials say no infections linked to the infected individual have been reported to date.

Commenting on the matter, Seattle-based public health worker Elysia Gonzales said: ‘Measles is highly contagious and if you don’t have immunity, you can get it just by being in an area where a person with measles has been.

‘We’ve seen an increase in measles cases around the world and in the US, so it’s an important time to check your vaccination status and get vaccinated if you aren’t protected.’

Measles is one of the most infectious diseases in the world, with one person capable of spreading the virus to nine out of every 10 people they meet if those individuals are unvaccinated.

Measles is transmitted via breathing in infectious droplets that can remain suspended in the air for two hours after an infected patient passes.

Patients develop a fever, cough, and runny nose, which then develops into a rash that starts at the hairline before spreading to the neck, trunk, arms, legs and feet.

There’s no cure for measles, with doctors instead using antibiotics to treat related infections and IV fluids. 

If unvaccinated, about one in five people who are infected are hospitalized while one in 20 children develop pneumonia.

Among unvaccinated children infected with measles, about one in 1,000 will develop encephalitis — or swelling of the brain. And nearly one to three out of every 1,000 will die from the disease.

The vaccine is 97 percent effective at preventing an infection and is required for children attending school in some states.

In terms of when to get vaccinated, Gonzales says: ‘Children need two doses of MMR vaccine: the first dose at age 12-15 months, and the second dose at age 4-6 years. 

‘Babies ages 6-11 months should get an early dose if traveling internationally. Adults should also check to see if they are immune to measles.’