Health Alert: Measles Case in Visitor to King and Snohomish Counties 

 May 14, 2025 

Action Requested 

Be aware of possible measles exposures in King and Snohomish County from 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.  

• Secondary cases would be expected to occur May 7, 2025 – May 24, 2025.

Isolate  

• Have a planned triage process for patients with fever and rash so these patients are not waiting in common areas with other people. 
• Patients with rash and fever should not stay in waiting rooms or other common areas. 
• Immediately isolate patients with suspected measles in an airborne infection isolation room (AIIR) or a private room with a closed door. 
• Follow standard and airborne precautions when evaluating suspected cases, regardless of vaccination status.
• After patient is discharged, do not use or have staff enter the room for 2 hours.

Notify 

• Report suspected measles cases to the Snohomish County Health Department at (425) 339-3503 immediately AND before discharging or transferring patients.
• Public Health will ensure appropriate, rapid testing and investigation.

Test 

• Collect the following specimens on patients with suspected measles:
• Nasopharyngeal swab placed in viral transport media; AND
• Urine, minimum 20mL, in sterile leak proof container; AND
• Serum, minimum 1mL, in red top or red-grey top tube
• Public Health will facilitate diagnostic testing with Washington State Public Health Laboratory (WAPHL).

Manage 

• Health care facilities should inform their Infection Prevention Program to identify potentially exposed persons at the facility (patients, visitors, staff, and volunteers).
• Public Health will identify close contacts and recommend post-exposure prophylaxis (PEP) for eligible people.
• If a patient requests titers to determine immunity, providers should accommodate this request. If the patient is concerned about potential recent exposure, take appropriate precautions, including drawing titers outdoors when no AIIR is available if it has been more than 72 hours since exposure.

Vaccinate 

• Assess immunization status during healthcare visits at every visit and strongly recommend measles, mumps and rubella (MMR) vaccination based on the recommended schedule, health condition, occupation, and other risk factors such as travel.
• If you are reviewing your client’s immunization record in the state immunization registry (WAIIS), please note that the first section displayed is the ‘forecast,’ which will outline any due or overdue immunizations. The forecast section does not confirm that a vaccine has been given, only that one (or more) are due.

• Under-vaccinated individuals may be at risk for measles infection due to outbreaks that occur in the US or anywhere else in the world. 
• If you are treating pediatric patients 6-11 months old, please inquire about upcoming international travel, or potential travel to an area with a measles outbreak. If there is upcoming travel that could result in measles exposure, offer a single MMR single vaccine dose for protection in case of an exposure. The two standard doses of the MMR vaccine, starting at 12 months, will still be required.
• If you are running low on critical supplies, including doses of the MMR vaccine, and have exhausted all local options for additional supplies, you can contact the NWHRN duty officer (425.988.2897), who can help you fill out a resource request to the state or source mutual aid from other healthcare facilities.

Background 

A case of measles was identified 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. If a person was at a listed location below, during the noted dates and times, and they are not immune to measles, the most likely time a person would become sick would be between May 7– 24, 2025. 

There is no ongoing risk for measles exposure at these locations.  

Measles illness starts with a prodrome of fever, cough, coryza, and conjunctivitis (typically lasting 2-4 days) and then a generalized maculopapular rash that typically begins on the face/head then spreads to the neck, trunk and extremities. Increases in measles cases and outbreaks are occurring in every region of the world.  

CDC recommends all U.S. residents aged 6 months and older without evidence of immunity, who plan to travel internationally, get the MMR vaccine at least 2 weeks prior to departure. Infants 6 to 11 months of age who get the MMR vaccine before international travel should get an additional 2 doses of MMR according to the recommended schedule, after 1 year of age.  

For further guidance or to report a case, contact Snohomish County Health Department at:  (425) 339-3503 

shd-CDQuestions@co.snohomish.wa.us 

Resources 

• For Healthcare Providers
  • Measles One-Pager for Healthcare Providers – Project Firstline and AAP
  • Measles - For Healthcare Professionals– CDC
  • Measles Specimen Collection Instructions for RT-PCR – WA DOH
  • Measles Specimen Collection Instructions for Serology – WA DOH
  • Immunization Schedules – CDC
  • Safety Information for Measles, Mumps, Rubella (MMR) Vaccines – CDC
  • Measles Assessment Checklist – WA DOH
• For Infection Preventionists
  • Interim Measles Infection Prevention Recommendations in Healthcare Settings – CDC
  • Measles Playbook – APIC Emerging Infectious Diseases Task Force
• For Laboratories
  • Public Health Laboratories Lab Test Menu – WA DOH
  • Measles Specimen Shipping Guide – WA DOH 
• For General Public and International Travelers
  • Measles Resources – PHSKC
  • Plan for Travel – Measles – CDC