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January 16, 2026

Measles outbreak declared in Snohomish County

➜ This health advisory is also available in PDF format (189 KB)

Actions requested

Be aware of three new confirmed measles cases in Snohomish County children exposed to recent measles cases in visitors to Snohomish and King Counties.

  • Visit the Snohomish County measles website to view more specific information about potential areas of exposure within Snohomish County.  There are no new reported potential King County exposure locations for these Snohomish cases. 
  • Secondary cases would most likely occur between January 16 - February 3, 2026.  
  • MMR vaccination remains the most important tool for preventing measles infections and spread from imported and local cases.

Refer to Measles actions for Healthcare Providers for more details on immediate isolation, notification, testing, and management of patients with suspected measles, plus vaccination information and resources. 


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