Across Oregon, 22 measles cases have been reported, with 21 occurring among individuals who were unvaccinated or whose vaccination status was unknown. Multnomah County has experienced multiple confirmed cases and numerous exposures, reinforcing how quickly measles can spread in a densely populated area and how critical rapid public health action is. 

During this response, Multnomah County faced several large-scale public exposures. Locations included a grocery store, café, clinics, schools and restaurants; settings where identifying all exposed individuals is often difficult. One grocery store exposure alone involved approximately 100 potentially exposed staff members. 

Another significant exposure occurred in a middle school, where 140 staff were identified as potentially exposed. Determining vaccination status for such a large group proved challenging. Many individuals did not have immediate access to immunization records, and verifying status required extensive time and coordination from an already stretched team. 

In total, 31 unvaccinated students were placed on active monitoring and quarantine. Families were asked to keep students’ home for the full 21-day measles incubation period. Following this period, no illnesses were reported among the children or staff, an outcome that reflected the effectiveness of quarantine, monitoring, and follow-up efforts. 

Not all exposure investigations allow for complete contact tracing. In one instance, a public exposure occurred in which not every potentially exposed individual could be identified. In response, Multnomah County issued a public announcement informing community members that anyone present at a specific location during a specific timeframe may have been exposed to measles. 

Following this announcement, one individual was identified as a possible measles case. The individual met the confirmed case definition, presenting with a febrile rash illness and a known exposure to measles. Because their vaccination status could not be confirmed, the health department proceeded under the assumption that they were unvaccinated and asked them to quarantine while awaiting test results. This cautious approach reflected standard public health practice aimed at reducing the risk of further transmission. 

One of the most persistent challenges during this response involved locating adult vaccination records. Oregon did not have an online immunization information system in place prior to 1996, which means many adults have no easily accessible documentation of their measles vaccination status. As a result, individuals often struggled to confirm immunity during exposure investigations, creating delays and additional workload for the health department. 

To address this issue proactively, the health department began encouraging adults to search for their vaccination records ahead of time, rather than waiting until an exposure occurs. Early preparation can reduce stress for individuals and allow public health staff to act more quickly and efficiently during an outbreak response. 

Historically, the Multnomah County Health Department has been highly effective at building relationships with families, including those who are vaccine hesitant or distrustful of government systems. The Communicable Disease team emphasizes meeting people where they are, practicing empathy, and maintaining open, respectful communication. These approaches have previously led to strong outcomes, such as families adhering to isolation recommendations and proactively contacting the LHD when symptoms arise. 

This year, however, the team observed a shift. Some individuals were more reluctant to disclose symptoms or reach out when illness occurred. In the middle school exposure situation, two students were sent to school during an incubation period despite being under active monitoring. The health department had checked in regularly with the family, and no symptoms were initially reported. Through an established partnership with the school district, the health department later learned that the students had missed school due to illness. When the family was contacted again, it was acknowledged that the children had been sick and had attended school while symptomatic, leading to additional exposures. 

This experience highlighted the challenges of relying solely on self-reporting and reinforced the importance of strong, two-way communication channels. 

In response to these challenges, the Multnomah County Health Department continues to prioritize partnerships with schools, workplaces, healthcare providers, and community organizations. These relationships provide additional layers of communication, verification, and shared responsibility during outbreak responses. Collaboration with schools proved critical in identifying gaps in reporting and preventing further transmission. 

Multnomah County remains committed to rebuilding and sustaining trust with community members while also strengthening institutional partnerships. Transparency, consistency, and empathy remain central to their approach, even when situations are difficult or outcomes are imperfect. 

The measles response in Multnomah County underscored both the strain on local public health systems and their resilience. A small team managing widespread exposures in a densely populated county is a significant undertaking, but strong partnerships, proactive communication, and careful monitoring made a meaningful difference. The absence of secondary cases among quarantined students and staff demonstrated the value of timely intervention. 

As the health department looks ahead, lessons from this response are shaping future preparedness efforts: encouraging early vaccine record retrieval, reinforcing cross-sector partnerships, and continuing to invest in trust and communication. In a county as dynamic and populous as Multnomah, these strategies remain essential to protecting community health. 

This information was presented on a NACCHO webinar by Sara McCall, Communicable Disease Program Manager at the Multnomah County Health Department. To learn more about this work and measles preparedness, listen to the full NACCHO Webinar Measles Preparedness and Response: CDC Updates and Local Lessons from the Field