Measles case associated with international travel in a Snohomish County resident

Actions requested

➜ This health advisory is also available in PDF format (157 KB).

Be aware of a confirmed measles case in a Snohomish County infant with international travel.

• See table below for public exposures in King and Snohomish counties while infectious
• Secondary cases would most likely occur between April 3 – April 21, 2025

Consider measles as a diagnosis in anyone with fever (≥101°F or 38.3°C) and a generalized maculopapular rash with cough, coryza, or conjunctivitis who has recently traveled internationally, or domestically to a region with a known measles outbreak, or has other known or suspected exposure to measles:

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

Ensure all patients without evidence of immunity are up to date on MMR vaccine per routine ACIP recommendations, especially for international travelers (regardless of the destination) or domestic travelers to outbreak area:

• Children are routinely recommended to receive 2 doses of MMR, the first at 12–15 months of age and the second at 4–6 years of age before school entry.
• Adults not at high risk of exposure are recommended to have at least 1 documented dose of MMR in their lifetime, or other evidence of immunity (e.g., positive measles immunoglobulin G (IgG)).
• Adults at high exposure risk, including students at post-secondary institutions, healthcare workers, and international travelers, should receive 2 doses.
• For any international travel: also recommend infants 6-11 months of age get an early dose of MMR at least 2 weeks prior to departure.
• An early dose of MMR before the first birthday does not count as part of the routine 2-dose series.
• For any domestic travel to outbreak areas, consider the same approach as for international travelers prior to departure:
• An early MMR dose for infants 6-11 months of age
• A second MMR dose for anyone eligible who is 12 months of age or older (2 doses at least 28 days apart)

Background

Public Health is investigating a case of measles in a Snohomish County infant most likely exposed during international travel. This new measles case is not linked to the two previously confirmed measles cases in Washington state. Two of the three recent cases in Washington have been infants.

The infant was at the following locations during their infectious period before being diagnosed with measles (time for exposure includes the period when at the locations and two hours after):

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

MMR vaccination remains the most important tool for preventing measles infections and spread from imported cases. Two doses of MMR vaccine provide 97% protection against measles while one dose provides 93% protection.