On Apr. 22, 2025, 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.

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.

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.