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April 22, 2025
Fifth case of measles in Washington state identified in a King County infant
Public Health – Seattle & King County was notified of a confirmed measles case in a King County infant. The individual traveled through Seattle-Tacoma International Airport (SEA) and was at some specific locations at Seattle Children’s Hospital while infectious. The individual was likely exposed to measles during recent international travel. The infant had not yet been vaccinated.
This case is not connected to any of the previous local measles cases. This is the fifth case of measles in Washington state in 2025, three of which have been infants. In addition, Public Health – Seattle & King County responded to two other measles cases this year among people who traveled through King County but are not Washington state residents.
“Measles outbreaks are happening in every part of the world. If you are planning international travel, it’s important to speak with your healthcare provider about what vaccines may be needed. 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,” said Elysia Gonzales, Medical Epidemiologist for Public Health – Seattle & King County.
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.
Locations of potential exposure to the public
Note: Exposure dates and times at Seattle Children's revised on 4/23/25.
Spread of measles can occur before people know they have the disease, before a 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:
| Date | Time | Location |
|---|---|---|
| 4/15/25 | 4:50 pm - 7:45 pm |
Seattle-Tacoma International Airport
|
| 4/17/25 | 8:45 am - 5:30 pm - |
Seattle Children's Emergency Department
|
| 4/17/25 | 5:30 pm - |
Seattle Children’s Emergency Department
|
(Corrected information) 4/18/25 |
11:50 am - 3:30 pm |
Seattle Children’s Emergency Department
|
(Corrected information) 4/20/25 |
12:05 pm - 2:25 pm |
Seattle Children’s Emergency Department
|
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 April 22, 2025 – May 11, 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: kingcounty.gov/measles