Updated Guidance Related to Clark County, WA Measles Outbreak

Posted Feb. 4, 2019. Past health advisories and alerts are archived for historical purposes and are not maintained or updated.

Measles Outbreak Testing Guidance Through Public Health LaboratoriesMeasles Prophylaxis and Treatment Guidance
For Healthcare Providers - Measles

New in this advisory: outbreak testing guidance, atypical/modified measles presentation, immunization recommendations, and treatment/prophylaxis guidance.

UPDATED: The measles outbreak in Vancouver, WA/Portland/OR metropolitan area is continuing. As of January 31, 2019, 41 cases of measles have been identified in Clark County with an additional 15 suspect cases under evaluation.  Additionally, one case has been identified in Seattle/King County and one in Portland/Multnomah County, OR. In Clark County, all but one case was in children 18 and under. All cases are unvaccinated (37) or unverified vaccination history (4). The number of exposed individuals is in the thousands. A complete list of exposure sites for the Vancouver area; Portland, OR; and Bend, OR is maintained here: clark.wa.gov/public-health/measles-investigation. At this time, we do not know whether any Spokane residents have been exposed. 

Spokane Regional Health District (SRHD) continues to ask that you consider measles in patients with the symptoms listed below, particularly if they report travel to the Vancouver, WA/Portland, OR metropolitan area in the 21 days prior to rash onset.

Please use the attached Guidance for Outbreak Measles Testing Form when submitting tests through public health. This form is available on our website: srhd.org/for-health-care-providers and it replaces the “Measles Quick Assessment” form attached to our previous advisory.

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 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 7 to 21 days after exposure and a person ill with measles is contagious for about four days before rash appears until four days afterward.

NEW: According to the CDC Pink Book Chapter on Measles, atypical measles occurs only in persons who were vaccinated with inactivated measles vaccine and are subsequently exposed to wild-type measles virus. Inactivated measles vaccine was only used during 1963-67 and an estimated 600,000-900,000 persons received this vaccine in the United States. Atypical measles is characterized by fever, pneumonia, pleural effusions, and edema. The rash appears first on the wrists or ankles and is usually maculopapular or petechial, but may have urticarial, purpuric, or vesicular components.

NEW: Modified measles occurs primarily in persons who received immune globulin as a post-exposure prophylaxis and in young infants who have some residual maternal antibody. It is characterized by a prolonged incubation period, mild prodrome, and sparse discrete rash of short duration. Similar mild illness has been reported among previously vaccinated persons.

More information on the clinical features of measles can be found here: 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 4 to 6 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. For more information, see cdc.gov/vaccines/vpd/mmr/public/index.html.

NEW: The ACIP has not recommended changes to the vaccine schedule in light of this outbreak. However, providers can always use their own discretion to accelerate the two dose MMR schedule and provide a second dose of MMR prior to a child’s 4th birthday, as long as the two doses are separated by at least 28 days. Vaccination in 6-11 month old children is currently recommended for infants traveling internationally; however, guidelines do not specifically name travel to domestic outbreak areas

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.

NEW: Guidance for Measles Prophylaxis and Treatment is attached to this advisory, courtesy of Colleen Terriff, PharmD, MPH, Multicare Deaconess Hospital. 

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. 

SRHD Epidemiologists are available 24/7 for consultation on laboratory diagnosis of measles at 509-869-3133.

Suspected or confirmed cases of measles are immediately notifiable and should be reported to Spokane Regional Health District Epidemiology at 509-869-3133.