Home / Health / Oregon Measles Outbreak: Wastewater Detects Virus
Oregon Measles Outbreak: Wastewater Detects Virus
20 Feb
Summary
- Oregon declared a measles outbreak on February 19, with five confirmed cases.
- Wastewater monitoring detected measles in nine Oregon counties, indicating wider spread.
- Childhood measles vaccination exemption rates in Oregon reached a historic high in 2025.
The Oregon Health Authority declared a measles outbreak on February 19, reporting five confirmed cases since the start of the year. Wastewater monitoring has further revealed the presence of measles in nine Oregon counties during the two weeks ending February 7, indicating a potentially wider, undetected spread.
Of the confirmed cases, four were among unvaccinated individuals, with the vaccination status of the fifth unknown. Nationwide, nearly 1,000 measles cases were reported in 2026, a significant increase from the 2,300 cases in 2025. Oregon's wastewater monitoring, which began in October 2025, supplements confirmed case data, though it cannot trace individual infections.
Oregon has required measles vaccination for kindergarten entry since 1998, but exemption rates have climbed, reaching nearly 1 in 10 kindergartners in 2025. Measles is highly contagious and can cause serious complications, including pneumonia and encephalitis. Health officials urge residents to reconsider vaccination decisions as cases rise nationally and within the state.
