State health officials are warning of growing risks of vaccine-preventable disease outbreaks in Oregon schools as childhood vaccination rates continue to decline and nonmedical exemptions reach record levels.
According to new data released by the Oregon Health Authority (OHA), the percentage of kindergarten students with nonmedical exemptions from required school vaccinations rose to 10.9% during the 2025-26 school year, the highest rate ever recorded in the state. The exemption rate has increased significantly from 6.9% in the 2021-22 school year.
At the same time, only 85.6% of Oregon kindergarteners are fully up to date on required vaccinations, continuing a downward trend that has persisted for more than a decade. State officials noted that the sharpest decline has occurred over the last four years, with vaccination coverage dropping three percentage points since the 2021-22 school year.
“Although the vast majority of families in Oregon are still choosing to protect families through vaccination, the downward trends are deeply concerning,” said Howard Chiou, M.D., Ph.D., medical director for communicable diseases and immunizations at OHA’s Public Health Division. “We risk seeing the return of diseases such as measles and polio—diseases of the past that once caused widespread harm but are entirely preventable with vaccines.”
The largest increase in exemptions has been recorded for the second dose of the measles, mumps and rubella (MMR) vaccine. Nonmedical exemptions for the second MMR dose among kindergarteners reached 9.4% this year, nearly double the 4.9% rate reported a decade ago.
Health officials emphasized that measles remains one of the most contagious diseases in the world and that vaccination is the most effective protection against infection.
The DTaP vaccine, which protects against diphtheria, tetanus and pertussis (whooping cough), had the second-highest exemption rate among kindergarten students. Concerns over pertussis are heightened after Oregon recorded 1,475 cases in 2025, the highest number reported in the state in 75 years.
Nationally, both measles and pertussis cases have surged over the past year, according to public health officials.
While statewide vaccination coverage remains higher among older students, OHA said local vulnerabilities persist. Approximately 90.2% of Oregon students in grades K-12 are up to date on required immunizations, but schools with lower vaccination rates are found in every county across the state.
“Even when overall vaccination rates are high at the state or county level, that can sometimes hide significant risk at an individual school, so parents should not assume their local schools will also be well protected,” Chiou said. “We encourage families to look at the immunization rates for their child’s school to better understand personal and community risks.”
Public health experts estimate that between 92% and 94% of a population must be immune to measles through vaccination or previous infection to prevent widespread transmission. OHA officials say they target a 93% vaccination rate to maintain herd immunity.
Current data show that more than one-third of Oregon schools with at least 10 students—36%—have MMR vaccination rates below the 93% threshold, placing them at elevated risk for a measles outbreak.
OHA is encouraging parents and guardians to review vaccination rates at their children’s schools through the agency’s School Immunization Data dashboard and ensure students are current on recommended immunizations before the next school year.
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