Five New Confirmed WA Measles Cases with SeaTac Exposures

Posted May 15, 2019. Past health advisories and alerts are archived for historical purposes and are not maintained or updated.

Five new cases of measles have been diagnosed since Sunday May 12. One is a Pierce Co resident in his 40s who spent time at SeaTac Airport. The other 4 cases are all residents of western WA counties. While the exact exposure information for the new cases is not yet known, all spent time in SeaTac airport during their likely time of exposure or infectiousness. Find more details on places the new cases visited when they were infectious at Public Health — Seattle & King CountyTacoma-Pierce County Health Department and Snohomish Health District websites. 

The Pierce County case’s rash onset was May 10/11, so he was exposed sometime between April 19 and May 1, 2019. Subsequently, this patient worked at SeaTac during the infectious period. Exposures in the community as a result of this case occurred between May 6 and May 11. We would expect cases from these exposures to occur between May 13 and June 1, 2019. Many exposed persons may have returned to other counties in the state after air travel.  At this time, we do not know whether any Spokane County residents were exposed. 

Recommendations:

  1. Assess patients with measles symptoms for local exposures (listed on next page), domestic or international travel to areas where measles outbreaks are occurring, or potential exposure to a confirmed measles case.
  2. Collect specimens on patients with suspected measles:
    1. Nasopharyngeal swab (preferred respiratory specimen) for PCR and virus isolation
    2. Urine (at least 50 ml) for PCR and virus isolation
    3. Serum (at least 1 cc) for measles
    4. All specimens for suspect measles cases must go to Washington Public Health Laboratory (WAPHL) with the form found here: https://doh.wa.gov/Portals/1/Documents/5230/302-017-SerVirHIV.pdf. Please take care when coordinating with your clinical laboratory to ensure they forward the specimens appropriately, or significant delays will occur. Please do not send specimens to a commercial laboratory.
  3. Report suspected or confirmed cases of measles to SRHD Epidemiology at 509-869-3133. 
    1. SRHD Epidemiologists are available at this number 24/7 for consultation on laboratory diagnosis of measles.

Evaluation of Persons with Suspected Measles:

  • Have patient enter through a separate entrance to the facility (e.g., dedicated isolation entrance) if available, to avoid the reception and registration area. If possible, the patient may also be scheduled at the end of the day to limit exposure to other patients/staff.
  • Place the patient immediately in a negative pressure or airborne infection isolation room (AIIR).
    • If an AIIR is not available:
      • Provide a facemask (e.g., procedure or surgical mask) to the patient and place the patient immediately in an exam room with a closed door.
      • Instruct the patient to keep the facemask on while in the exam room, if possible, and to change the mask if it becomes wet.
  • Only staff with documented immunity to measles (two valid, documented doses of MMR vaccine or a positive IgG titer) should be allowed to be in the exam room with the patient.
  • PPE use: Wear a fit-tested N-95 (or higher level) disposable respirator if available when caring for the patient; the respirator should be donned prior to room entry and removed after exiting room.
  • Instruct patient to wear a facemask when exiting the exam room, avoid coming into close contact with other patients, and practice respiratory hygiene and cough etiquette.
  • Once the patient leaves, the exam room should remain vacant for two hours before anyone enters.  If staff must enter the room during this time, they are required to use respiratory protection.
  • Instruct patients suspected of having measles to isolate for four full days after the onset of the rash.

Symptoms & Incubation:

Measles is characterized by a generalized maculopapular rash, fever, and one or more of the following: cough, coryza, or conjunctivitis. Measles has a distinct prodrome that begins with fever and malaise. Additional symptoms can be conjunctivitis, coryza, cough, photophobia, and Koplik’s spots (which are pathognomonic but uncommonly observed). These spots are bluish-white specks on a rose-red background appearing on the buccal and labial mucosa usually opposite the molars. Temperatures may exceed 104⁰F, and usually fall two to three days after rash onset.

 The prodrome generally lasts two to four days before the rash occurs. The rash is maculopapular and begins on the head often along the hairline and spreads downward reaching the hands and feet. After about five days, the rash fades in the same order in which it appeared. Measles is highly contagious, can cause pneumonia and encephalitis, and can be fatal.

Measles symptoms begin seven to 21 days after exposure and a person ill with measles is contagious for about four days before rash appears until four days afterward.  More information on the clinical features of measles can be found here: www.cdc.gov/measles/hcp/index.html.

Vaccination Recommendations:

Most people in our state are immune to measles, so the public risk is low except for people who are unvaccinated, pregnant women, infants, and those with compromised immune systems.

  • Children should be vaccinated with two doses of MMR vaccine, with the first dose between 12 and 15 months and the second at four to six years.
  • Adults should have at least one measles vaccination. One dose of MMR is 93% effective at preventing measles; two doses is 97% effective.
  • Those born prior to 1957 are considered immune. See www.cdc.gov/vaccines/vpd/mmr/public/index.html.

Laboratory Diagnosis of Measles:

The diagnosis of measles can be made by isolation of measles virus from a clinical specimen. Urine and respiratory samples are both good clinical specimens for viral isolation. Measles virus isolation is most successful when samples are collected within three days of rash onset. However, virus may still be present in specimens seven days following rash onset. WA State Public Health Lab can perform expedited RT-PCR on nasopharyngeal and urine specimens of measles on suspect cases; pre-approval from Spokane Regional Health District is required prior to submission.

The laboratory diagnosis of measles can also be made by detection of measles IgM antibody in a single serum specimen. Approximately 80% of measles cases in unvaccinated people have detectable IgM antibody by IgM capture EIA within 72 hours of rash onset. In most instances, a serum sample should be collected for measles IgM at the first clinical encounter. However, if a negative result is obtained from a specimen drawn less than 72 hours after rash onset, another specimen will be required. Additionally, persons vaccinated against measles may have a blunted or transient production of IgM; therefore, a negative IgM in vaccinated persons suspected of having measles should not be used to rule out the case.

Attachments & Resources:

Measles Testing Guidance/Reporting FormSRHD Measles Webpage
Measles Specimen Shipping GuideWA Department of Health Measles Webpage
Measles Prophy & Treatment GuideCDC Clinician Outreach Webinar on Measles – May 21, 11:00 am