Health officials in Snohomish County and King County, Washington report being notified of three confirmed measles cases recently. The three cases, all within the same family, one adult and two children visiting from South Carolina, were infectious from Dec. 27, 2025, through Jan. 1, 2026, while visiting King and Snohomish counties.
The adult had received at least one vaccine to protect against measles; the children were unvaccinated.
The family visited multiple locations in Marysville, Mukilteo and Everett while contagious – but before being diagnosed – with measles. They also traveled through Seattle-Tacoma International Airport and visited a car rental facility near the airport.
The Snohomish County Health Department published the following locations of potential exposure to the public:
If you are not immune to measles, or don’t know your vaccination status, please see the list below for locations and times of potential exposure.
Health officials urge residents to check their status for the MMR (measles, mumps and rubella) vaccine, which offers the best protection against the disease.
“Measles is one of the most contagious diseases we know, and often brings serious illness,” said Dr. James Lewis, Snohomish County Health Officer. “The MMR vaccine is the best way to prevent outbreaks and protect our community, especially for infants and those who cannot be vaccinated.”
The measles vaccine is extremely safe and incredibly effective. Two doses provide about 97% protection against getting infected by measles. The protection lasts a lifetime.
In 2025, 2,144 cases were reported to the CDC in 2025, the highest level since 1992.
In South Carolina, where a very active outbreak is ongoing, 434 cases have been reported as of January 13.