Overview
- Testing at the University of Washington Medicine Clinical Virology Lab identified H5N5, and the Centers for Disease Control and Prevention confirmed the result.
- The patient, an older adult from Grays Harbor County with underlying conditions, was hospitalized in King County in early November and died on Nov. 21.
- Environmental sampling detected avian influenza in the backyard flock setting linked to the patient, and the source investigation remains ongoing.
- Contacts and healthcare workers are being monitored for symptoms, and no additional human infections or evidence of person-to-person spread have been found.
- H5N5 is distinct from H5N1; experts say it is not expected to pose a greater risk to people than H5N1, which has caused about 70 U.S. infections since 2024.