Clinician Alert: Additional Measles Outbreak in Oregon, PCR Testing Recommended

July 12, 2024

Update: July 19, 2024

The suspect case reported in Multnomah County on 7/12/24 is now a confirmed case in an unvaccinated child. The child and their family recently spent time abroad in an area where measles is more common. Additional cases among other unvaccinated people within the child’s household are expected. However, we are optimistic that community spread will not occur from this case. The child did receive care in a healthcare setting while infectious. However, for any potential healthcare exposures, the health system will contact people directly. This case is unrelated to other ongoing measles activity elsewhere in Oregon. 

While measles is circulating in Oregon, the Oregon State Public Health Lab (OSPHL) will conduct PCR testing of specimens from suspected measles cases without prior public health approval. Submit appropriate specimens directly to OSPHL if both of the following criteria are met:

  1. The patient has rash illness compatible with measles and with no other explanation for the clinical presentation, AND
  2. The patient is unvaccinated or under-vaccinated for measles (fewer than 2 doses of measles-containing vaccine).

Recent reports confirm ongoing community transmission of measles among susceptible individuals.  

Local Public Health Authorities have identified 1 new confirmed, 2 presumptive, and 1 suspect case of measles in Marion and Multnomah Counties over the past week. 

In the June 17, 2024 Clinician Alert, we gave notice of 3 confirmed measles cases. Case investigation is ongoing to learn whether the new cases are linked to these previous cases. At this time, the current suspected case in Multnomah County is thought to be a separate travel-related case and not linked to the other cases.

Please read regarding preferred testing if you suspect measles.

Watch for symptoms of measles among your patients: prodrome of fever, cough, coryza, and conjunctivitis, followed a few days later by maculopapular rash that typically starts at the hairline, face, or neck, and spreads to the trunk and extremities. 

Prioritize PCR testing at Oregon State Public Health Lab (OSPHL) over serologic testing and your usual clinical lab for susceptible patients with symptoms compatible with measles.

If you suspect measles: 

  • Collect swab
  • Call the local public health authority (LPHA)
  • Isolate cases
  • Vaccinate contacts and consider post-exposure prophylaxis (PEP). 

Testing

Collect ALL of the following specimens when possible, listed in order of preference:

  1. Nasopharyngeal (NP) swab for measles PCR. This is the preferred test for diagnosis given high sensitivity and reliability early in disease:
    1. NP swab should be collected 0–5 days after rash onset; after 5 days, NP swab should be accompanied by urine.
    2. Throat swab is also acceptable.
  2. Urine for measles PCR:
    1. Urine PCR test is most sensitive 3–10 days after rash onset.
  3. Serum for measles IgM and IgG testing:
    1. Measles-specific IgM antibody may not be present until ≥3 days after rash onset but persists for about 30 days after rash onset.
    2. A positive IgG early in illness may suggest prior immunity.
    3. (Note: If specimens are sent to reference laboratories, these tests can take multiple days to weeks to result; for faster results, PCR testing at OSPHL is strongly recommended).

Timely laboratory confirmation of measles is critical to tracking the spread and prioritizing prevention efforts. Tests for measles can be ordered from most commercial labs or through the Oregon State Public Health Laboratory (OSPHL). Testing through the OSPHL is preferred, since it typically has a much faster turnaround time (usually within 3 days of specimen receipt), but approval is required from the Local Public Health Authority (LPHA, health department) for the county of residence of the patient (note: counties in Washington State do not require approval before sending to state lab). 

Instructions for testing in Oregon -- also has a link to the OSPHL Virology/Immunology Test Request Form.

Measles Investigative Guidelines contain detailed information about evaluation, testing, treatment, PEP, and prevention.

Call the appropriate LPHA immediately if you suspect measles. These tests should be ordered for patients who may have been exposed if their evaluation shows:

  1. A compatible illness; AND
  2. Likely susceptibility to measles (i.e., unvaccinated, recent travel, and/or contact with someone with measles)

In Oregon, LPHA approval is required for PCR testing sent to OSPHL. Please do not delay swab collection for approval.  LPHAs may be reached 24 hours a day to report suspect cases and discuss testing:

  • Clackamas County Public Health: 503-655-8411
  • Marion County Public Health: 503-588-5621
  • Multnomah County Public Health: 503-988-3406
  • Washington County Public Health: 503-846-3594
  • Oregon Health Authority’s Epi OnCall if LPHA unavailable: 971-673-1111

Resources

Clinicians guide for testing for measles and other vaccine-preventable diseases (CDC)

Thank you for your partnership,

Sarah Present, MD, MPH, Health Officer, Clackamas County Public Health Division

Richard Bruno, MD, MPH, Health Officer, Multnomah County Health Department

Teresa Everson, MD, MPH, CPH, Deputy Health Officer, Multnomah County Health Department

Caroline Castillo, MD, Health Officer, Marion County Health and Human Services