Clinician Alert: Measles Outbreak in Oregon

Three cases of measles in two different households have been identified in June 2024.

Two cases of measles have been identified in a Clackamas County household. They were believed to have been exposed in Marion County between May 19 and June 4, 2024. The primary affected individual, an unvaccinated adult, was confirmed to have measles June 14. They developed a rash June 11. The location of exposure is currently unknown, which suggests there may be other unrecognized cases in Oregon. The second household member, an unvaccinated child, developed symptoms a few days later. Both individuals are recovering.

A third case of measles in Marion County is confirmed in a 4-year-old child. This child also developed a rash on June 11, and may have been exposed in the same time frame.

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We request that area clinicians:

• Keep measles on the differential for patients who present with compatible symptoms, especially if they report an exposure and/or are unvaccinated for measles. 

• Immediately notify your infection prevention team and the local public health authority (health department) where the patient lives if you suspect measles. See 24-hour contact information under the Resources section below.

• Encourage vaccination in individuals 12 months and older who have not started or completed measles vaccination. See full vaccination recommendations, including contraindications such as pregnancy. 

• Distribute this notification to clinicians in your organization and networks.

Public Health is working with the cases to identify and monitor close contacts. Exposures may have occurred during the cases’ evaluation and treatment. However, the healthcare facilities and the cases did take appropriate available precautions, so these exposures are likely low risk. 

People might have been exposed if they were in any of these areas during these times:

OHSU facilities

• Richmond Clinic’s Urgent Care area – Wednesday, June 12, 4:40–5:40 p.m.

• OHSU Emergency Department (adult area): Wednesday, June 12 6:00 p.m. – Friday, June 14, 7:15 p.m. (Risk here is believed to be low, as patient was masked and airborne precautions were implemented promptly)

Background 

Measles is a highly contagious virus that passes from an infected person to another through coughing or sneezing and is considered to have both droplet and airborne transmission. Common complications from measles include otitis media, bronchopneumonia, laryngotracheobronchitis, and diarrhea. Even in previously healthy children, measles can cause serious illness requiring hospitalization, including encephalitis, and more rarely delayed complications such as subacute sclerosing panencephalitis, a progressive neurological condition associated with high mortality. 

Measles can be prevented with the MMR (measles, mumps, rubella) vaccine. In our region, MMR vaccination rates for 2 year-olds have slowly and steadily declined since 2019, and are below the 95% goal for herd immunity, so this is a good opportunity to discuss immunization with your patients.

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.

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 in the county of residence of the patient (note: counties in Washington State do not require approval before sending to state lab).

• Lab testing for measles at OSPHL
• OSPHL test request forms and collection kits
• Measles Investigative Guidelines (OHA)

Please see below for Specimen Collection Guidance. Call the appropriate local health public authority 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

In Oregon, local public health authority approval is required for PCR testing sent to OSPHL, which is the recommended lab for testing measles suspects. Local public health authorities (at county health departments) may be reached 24 hours a day to report suspect cases and discuss testing: 

• Multnomah County Public Health: 503-988-3406
• Washington County Public Health: 503-846-3594
• Clackamas County Public Health: 503-655-8411
• Marion County Public Health: (503) 588-5621
• Or Oregon Health Authority Epi OnCall: 971-673-1111

Healthcare Infection Control

Alert your infection prevention team as soon as you suspect measles.

Measles primarily spreads to close and household contacts through large droplets, but can also be transmitted through the airborne route. According to CDC, the virus can be transmitted through the latter route up to 2 hours after a contagious patient coughed or sneezed. Preventing healthcare exposures is critical to keep high-risk groups safe. When possible, use phone triage and assessment to determine if patients who might have measles need to be seen in-person. 

If patients or caregivers are concerned about measles, inquire whether they know of any exposure to an identified case. Up-to-date vaccination status makes measles much less likely. 

Please implement these interventions in your clinical settings to minimize exposure to others:

• If a patient with possible measles arrives unexpectedly, require the patient to mask, and room them promptly (negative-pressure room if available), keeping the door closed.
• Report any possible measles cases immediately to the local public health authority of the county where the patient resides (see phone numbers under Resources below).
• If feasible and appropriate, schedule possible measles patients as the last patient of the day.
• If feasible and appropriate, consider patient evaluation outdoors at least 30 feet away from others.
• If possible, escort suspected measles patients into the building via an entrance that allows them to access an exam room without exposing others.
• Minimize the number of health care workers interacting with the patient. Caregivers should have documented immunity to measles and wear an N-95 mask or PAPR.
• Perform all labs and clinical interventions in the exam room if possible.
• The exam room should not be used for 2 hours after the patient has left.
• Patients who are under evaluation for measles should isolate at home until the diagnosis is clarified.
• Be aware that unvaccinated or undervaccinated children and staff can be excluded from school during their incubation period, and ensure your patients know that Public Health will follow up with any confirmed cases.

Prevention

Measles is best prevented by 2 doses of MMR or MMRV. In normal circumstances, the first dose is recommended at 12-15 months of age to avoid interference from maternal antibody. The definitive resource on the timing of the second dose is the CDC Pink Book, which states:

The second dose of MMR may be administered as soon as 4 weeks (28 days) after the first dose. Children who have already received two doses of MMR vaccine at least 4 weeks apart, with the first dose administered no earlier than the first birthday, do not need an additional dose when they enter school.

Post-exposure prophylaxis with IV immunoglobulin within 6 days after exposure is recommended for certain susceptible individuals who have been exposed to measles. Consult Oregon recommendations for post-exposure prophylaxis. In general, immunoglobulin is prioritized for susceptible individuals at risk for severe disease including:

• Infants under age 12 months (intramuscular IG 0.5 mL/kg, max 15 mL)
• Pregnant women without evidence of immunity (400 mg/kg IVIG)
• Severely immunocompromised persons regardless of vaccination history (400 mg/kg IVIG)

The MMR vaccine, if administered within 72 hours of initial measles exposure, and immunoglobulin (IG), if administered within six days of exposure, may provide some protection or modify the clinical course of disease among susceptible persons. However, vaccination should be offered at any interval following exposure in order to offer protection from future exposures.

Please note, there is a 5% chance of a vaccine rash after immunization—which could be confused with measles, especially if given during the incubation period after exposure, but this should not deter you from vaccinating. The MMR vaccine should not be used in pregnant or severely immunocompromised patients.

Manual for the Surveillance of Vaccine-Preventable Diseases: Measles (CDC)

Resources

Public information about the measles can be viewed and shared on the Multnomah County Health Department webpage.

Patients or clinicians may call their respective Local Public Health Authority’s Communicable Disease team if they would like to talk through their situation and get recommendations for next steps. Suspected measles cases may also be reported 24 hours a day via these same channels.

Clackamas County Health Department: Communicable Disease team 503-655-8411

Marion County Public Health Division: Communicable Disease team 503-588-5621

Multnomah County Health Department: Communicable Disease team 503-988-3406

Washington County Health Department: Communicable Disease team 503-846-3594

Thank you for your partnership,