Oregon has confirmed 45 measles cases in 2026, exceeding every recent annual state total as declining childhood vaccination coverage leaves more communities vulnerable. The count, current through Thursday, August 13, is well above the 31 Oregon cases recorded by the US Centers for Disease Control and Prevention in 2024. Axios reported the new milestone on Friday, citing state data and reporting by the Oregon Capital Chronicle.
Most of this year's confirmed infections are concentrated in Multnomah County, which includes Portland, according to Axios. Oregon Health Authority wastewater monitoring has also detected measles activity in Washington, Polk, Marion and Klamath counties. State officials say wastewater surveillance complements clinical testing because confirmed diagnoses may capture only a portion of infections, especially when people do not seek care or receive a test.
The increase comes as Oregon records historically low compliance with school vaccination requirements. Oregon Health Authority data show that 10.9% of kindergarten pupils had nonmedical exemptions from required vaccines in the 2025-2026 school year, up from 9.7% one year earlier and 6.9% in 2021-2022. The agency said more than one-third of Oregon schools had vaccination levels that could place them at risk during a measles outbreak. Those figures describe statewide coverage and do not establish the vaccination status or source of every current case.
Oregon's rise forms part of a broader US resurgence. CDC data updated for August 13 list 2,566 confirmed measles cases nationwide in 2026, already above the 2,289 recorded during all of 2025 and the highest annual count since 1991. The agency has counted 38 outbreaks this year and says 94% of confirmed infections, or 2,407 cases, are associated with outbreaks. National kindergarten coverage with the measles, mumps and rubella vaccine fell from 95.2% in 2019-2020 to 92.5% in 2024-2025, below the 95% level associated with community protection.
Measles spreads through the air when an infected person breathes, speaks, coughs or sneezes, and infectious particles can remain in a room for up to two hours. Symptoms commonly begin with fever, cough, a runny nose and red, watery eyes before a rash develops and spreads. The CDC says one MMR dose is about 93% effective at preventing measles and two doses are about 97% effective. Oregon officials advise residents to check vaccination records and to call a health provider before arriving if symptoms appear, allowing staff to prevent exposure to other patients.
The growing caseload is increasing the demands on local investigators who must identify contacts, notify exposed people and arrange testing or isolation. A Multnomah County spokesperson told the Oregon Capital Chronicle that the increase is straining the public-health response. Oregon plans to keep updating confirmed case totals each Wednesday while wastewater monitoring provides a second signal of where the virus may be circulating. Health officials say vaccination and prompt reporting remain the main tools for limiting further spread.
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