Tri-County Clinician Update
Four Multnomah County Measles Cases Confirmed
No spread to General Population
50 people, mostly unvaccinated children, from Clark County, Washington have confirmed measles; so far only one has been hospitalized. Use this link for updated information on the Clark County outbreak.
Four measles cases have now been confirmed in Multnomah County; all were unvaccinated. The three cases announced Feb. 6 had close, prolonged face-to-face contact with the first Multnomah County case. The first case was confirmed on January 25 and the other three on February 5th. There were no public or healthcare exposures related to the three recently confirmed cases because all complied with monitoring and quarantine instructions. There has been no documented spread of measles in Oregon beyond the cases directly linked to the Clark County outbreak.
We may continue to see cases in our region through the end of February 2019 based on the most recent exposures; this date may be extended as additional cases are identified.
Measles is a highly contagious, severe, febrile viral respiratory illness that is preventable by vaccination. In addition to prominent fever, respiratory symptoms and malaise, measles is characterized by cough, conjunctivitis and an extensive rash that typically begins the 2nd to 4th day of illness. Measles frequently causes diarrhea, ear infection and pneumonia; in recent years, approximately 30% of Oregon cases required hospitalization. Less frequent but feared complications include keratitis, corneal ulceration, blindness, encephalitis, and death. Infants, susceptible pregnant women and immunocompromised hosts may be at greater risk for serious complications of measles. Measles spreads easily in healthcare settings; your diligence and awareness will help prevent additional cases and prolongation of the outbreak.
Measles is best prevented by 2 doses of MMR or MMRV. In normal circumstances, the first dose is recommended between 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 immunoglobulin within 6 days after exposure is recommended for certain susceptible individuals who have been exposed to measles. Oregon recommendations are available here. 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)
Infants aged 6-12 months and other healthy contacts to measles cases should receive MMR vaccine as post-exposure prophylaxis if it can be given within 72 hours of exposure. MMR provides long term immunity and may prevent disease if given promptly. Even if the MMR vaccine is not given within 72 hours of exposure, the vaccine should be offered to provide protection from future exposures. MMR should not be used in pregnant women or severely immunocompromised patients.
Testing for measles
Laboratory confirmation of measles is critical to track the course of the outbreak and to prioritize prevention and prophylaxis efforts. Traditional measles IgM has poor sensitivity early in the illness and is only considered reliable if obtained 72 or more hours after rash onset. The Oregon State Public Health Laboratory (OSPHL) offers a sensitive RT-PCR test for measles that is more reliable early in the illness. This test can be requested by contacting the local health department of the patient if their evaluation shows:
A compatible illness; AND
Likely susceptibility to measles; AND
Exposure to a known case, a known public exposure or recent foreign travel to a county with on-going measles transmission
Note: Health department approval is required for this test.
Healthcare Infection Control
Measles primarily spreads to close and household contacts through large droplets but can also be transmitted through the airborne route, even after the patient is no longer present. CDC notes that the virus can live up to 2 hours in airspace where the infected person 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, consider whether they could have been exposed at the specified locations. Up-to-date vaccination status for age makes measles much less likely. If a patient needs to be evaluated in-person, or arrives unexpectedly with symptoms compatible with measles, consult with your health system infection control program and consider these options to minimize exposure to others:
If possible and appropriate, the patient may be scheduled as the last patient of the day.
If feasible, appropriate, and patient privacy can be protected, the patient can be briefly evaluated outside, at least 30 feet away from others. Once a mask is placed and a clear path to exam room prepared, the patient can be escorted into the building.
Whenever possible, the patient should be escorted from a separate clinic entrance that allows them to access an exam room directly without exposing others.
The number of health care workers interacting with the patient should be kept to a minimum.
If the patient is already in the clinic, the patient should be masked and roomed immediately rather than allowed to wait in the lobby.
The exam room door should remain closed at all times, and the patient should remain masked during the entire visit.
All labs and clinical interventions should be done in the exam room.
The patient should be evaluated seen by staff who are fully immunized against measles and wearing a fit-tested N-95 mask or powered air purifying respirator (PAPR).
The exam room should not be used for 2 hours until after the patient has left.
Any patient referred to an Emergency Department for evaluation should be placed immediately in a negative pressure room
Consider all relevant potential diagnoses; if measles is considered likely then specific testing can be facilitated by contacting the local health department. Patients who are likely to have measles but do not need inpatient admission should be instructed to isolate at home until measles is ruled out clinically or via testing.
Local Health Department Phone Numbers:
Thank you for your partnership,
Paul Lewis, MD, MPH, Health Officer, Multnomah County
Jennifer Vines, MD, MPH, Deputy Health Officer, Multnomah County
Sarah Present, MD, MPH, Health Officer, Clackamas County
Christina Baumann, MD, MPH, Health Officer, Washington County