About 26% of kindergartners in Hamilton County started the school year without vaccination records on file, a gap that health officials say could slow outbreak response at local elementary schools including those in the Princeton City School District.

Hamilton County Public Health medical director Dr. Steven Feagins told WLWT on Aug. 20 that the missing paperwork makes it harder to assess actual vaccine coverage across the county.

"That's a big deal for us, because let's say there's a potential elementary school where someone has measles, and so when we go in to contact trace and to understand who needs to be isolated, we have to assume that 26% without documentation have not had vaccinations," Feagins said. "Usually when we do that, the documentation does come forward."

Princeton City Schools' kindergartners began classes Aug. 17 across the district's eight elementary buildings in Evendale, Sharonville, Springdale, Woodlawn, Glendale and Lincoln Heights. Ohio law requires students to be vaccinated against 10 diseases, including measles, mumps and rubella, but schools have until Thursday, Oct. 15, to report immunization status to the state.

That reporting window matters now more than before.

The CDC reported that kindergarten vaccine exemptions nationally hit a record 4.2% for the 2025-26 school year, nearly double the 2.2% rate from 2020-21. Most exemptions were for non-medical reasons. The national MMR vaccination rate fell to 92.4%, below the 95% threshold doctors consider necessary for herd immunity against measles.

Ohio is already feeling the consequences. The Ohio Department of Health reported 69 confirmed measles cases across 11 counties as of Aug. 13, surpassing the state's entire 2025 total of 45 cases. It is the state's third measles outbreak of 2026.

Dr. Felicia Scaggs Huang, a Cincinnati Children's doctor, told WLWT that declining vaccination rates will lead to more vaccine-preventable diseases. Even patients who recover can face serious consequences such as hearing loss, she said, and outbreaks mean missed school days for children and missed work for parents.

Feagins emphasized that the 26% figure likely overstates the problem. Hamilton County's vaccination rates appear lower than they actually are because families have not submitted paperwork, not necessarily because children are unvaccinated. Still, without records on file, health officials must treat those students as unvaccinated during any outbreak investigation.

Parents who need to locate their child's vaccination records can contact their healthcare provider, their local health department, or submit an Ohio Department of Health Authorization to Disclose Form to access the state's ImpactSIIS immunization registry. Schools must have all immunization records reported to the state by Thursday, Oct. 15.