Two Measles Cases Identified in King County Linked to International Travel

Potential exposures reported in Seattle, Kirkland, and Bellevue areas

Apr. 1, 2026 at 11:26pm

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A translucent, ghostly X-ray-style image showing the detailed internal structure of a measles virus particle, rendered in shades of blue and purple against a dark background.An X-ray-like image reveals the intricate internal structure of the measles virus, a highly contagious pathogen that continues to pose a public health threat.Seattle Today

Public Health - Seattle & King County has reported two confirmed measles cases in adults who recently traveled internationally. The individuals visited multiple locations in the Seattle area while infectious, potentially exposing others to the highly contagious disease. Health officials are urging residents to ensure they are up-to-date on measles (MMR) vaccinations, especially before any upcoming travel.

Why it matters

Measles is a serious and potentially life-threatening illness that can spread rapidly, especially among unvaccinated populations. This incident highlights the ongoing risk of measles outbreaks in the region, even as vaccination rates remain high. Proactive steps to boost immunity and identify potential exposures are crucial to containing the spread of measles and protecting vulnerable community members.

The details

The two King County residents who tested positive for measles recently traveled internationally, where they were likely exposed to the virus. Their vaccination status is unknown. Before being diagnosed, the individuals visited multiple locations in Seattle, Kirkland, and Bellevue while infectious and able to spread the disease. Public health officials have identified the potential exposure sites and are urging anyone who may have been in those areas to check their vaccination status and watch for symptoms.

  • The two individuals were notified of their measles diagnosis on March 30, 2026.
  • The potential exposure period is from March 28, 2026 to April 20, 2026.

The players

Dr. Sandra J. Valenciano

Health Officer and Acting Director for Public Health - Seattle & King County.

Public Health - Seattle & King County

The local public health department that identified the measles cases and is leading the response effort.

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What they’re saying

“As we start traveling more during spring and summer months, we need to prepare for more potential exposure to measles, which is spreading in the U.S. and abroad. It's a preventable disease that can cause some serious complications, like swelling of the brain. Before you travel, check with your provider to make sure you and your family have had two doses of MMR vaccine or otherwise have immunity.”

— Dr. Sandra J. Valenciano, Health Officer and Acting Director

What’s next

Public Health - Seattle & King County has created educational resources for schools, workplaces, and healthcare providers to share information about measles prevention and response. Residents are encouraged to check their vaccination status and watch for symptoms if they visited the identified exposure locations.

The takeaway

This incident underscores the ongoing need for vigilance against measles, even in highly vaccinated communities. Ensuring up-to-date MMR vaccination, especially before travel, is the best defense against this highly contagious disease and its potentially serious complications.