MEASLES CASE IN VISITOR TO KING AND SNOHOMISH COUNTIES: MULTIPLE LOCATIONS OF POSSIBLE EXPOSURE 

This information is a redistribution of a release originally posted by Public Health – Settle & King County

Public Health – Seattle & King County was notified of a confirmed measles case in a Canadian resident. The person spent time in King and Snohomish counties between April 30 and May 3, 2025, while infectious. The individual’s vaccine status is unknown.  

In addition to traveling through Seattle-Tacoma International Airport, the person visited multiple public locations in Renton, Bellevue, Seattle, Everett and Woodinville while contagious with measles, but before being diagnosed with measles. If you are not immune to measles, or don’t know your vaccination status, please see the list below for locations of potential exposure. 

This case is not connected to any previous local measles cases. Public Health – Seattle & King County has responded to two other measles cases this year among people who traveled through King County but are not Washington state residents. There have been five cases of measles in Washington state residents this year.  

“Globally and in the U.S., we are experiencing a significant measles resurgence. With over 1,000 cases reported so far this year nationally, 2025 is on track to have the highest number of measles cases in the U.S. since the early 1990s,” said Meagan Kay, Medical Epidemiologist for Public Health – Seattle & King County. “It’s an important time to check your vaccination status and get vaccinated if you aren’t protected.”  

Fortunately, the measles vaccine is very effective. Two doses of measles, mumps and rubella (MMR) vaccine provides about 97% protection against getting infected by measles and that protection lasts a lifetime.  

For answers to frequent questions about measles, including how to protect your family if you’re traveling, visit our recent blog post.  

Locations of potential exposure to the public  

Spread of measles can occur before people know they have the disease, before any rash appears.  

The infected person was at the following public locations before being diagnosed with measles. These times include the estimated period when the individual was at the location and two hours after. Measles virus can remain in the air for up to two hours after someone infectious with measles leaves the area. Anyone who was at the following locations during the times listed could have been exposed to measles:  

What to do if you were in a location of potential measles exposure  

Most people in our area have immunity to measles through vaccination, so the risk to the general public is low. However, anyone who was in the locations of potential exposure to measles around the times listed should:  

• Find out if you have been vaccinated for measles or have had measles previously. Make sure you are up-to-date with the recommended number of measles (MMR) vaccinations.  
• Call a healthcare provider promptly if you develop an illness with fever or with an unexplained rash. To avoid possibly spreading measles to others, do not go to a clinic or hospital without calling first to tell them you want to be checked for measles after an exposure. It is also important to limit contact with others, especially those without known immunity.  

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 7– 24, 2025. People who are immuno-compromised may take longer to experience symptoms.  

About measles  

Measles is a highly contagious and potentially severe disease that causes fever, rash, cough, runny nose, and red, watery eyes. If one person has it, up to 9 out of 10 people nearby will become infected if they are not protected. It mainly spreads through the air after a person with measles coughs or sneezes.  

Measles symptoms begin 7 to 21 days after exposure. Measles is contagious from about 4 days before the rash appears through 4 days after the rash appears. People can spread measles before they have the characteristic measles rash.  

Measles can lead to ear infections, diarrhea, pneumonia, and rarely, encephalitis (brain inflammation) or death.  

Complications from measles can happen even in healthy people, but those at highest risk include infants and children under 5 years, adults over 20 years, pregnant people, and people with weakened immune systems from medications or underlying disease.  

If you are in one of these high-risk groups and were exposed to measles at one of these locations, be sure to contact your health care provider to discuss any steps you need to take to protect yourself or loved ones against complications from measles.  

Measles is preventable with the safe and highly effective measles, mumps and rubella (MMR) vaccine. Two doses of the MMR vaccine are about 97% effective at preventing measles and that protection is long lasting.  

For more information about measles and measles vaccination, including where to get measles vaccinations: https://www.snohd.org/460/Measles