A monthslong NBC News data investigation finds that much of the U.S. doesn't have the protection needed to stop the spread of deadly diseases. St. Louis is a window into the problem communities face nationwide.

One key finding of the analysis is stunning: A large swath of the U.S. currently does not have the basic, ground-level immunity medical experts say is necessary to stop the spread of measles, which had once nearly been eliminated. The data further reveals that:

  • Since 2019, 77% of counties and jurisdictions in the U.S. have reported notable declines in childhood vaccination rates. The declines span from less than 1 percentage point to more than 40 percentage points.
  • Vaccine exemptions for school children are rising nationwide: As many as 53% of counties and jurisdictions saw exemption rates more than double from their first year of collecting data to the most recent.
  • Among the states collecting data for the measles-mumps-rubella (MMR) vaccine, 68% of counties and jurisdictions now have immunization rates below 95% — the level of herd immunity doctors say is needed to protect against an outbreak.

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Student enrollment in Saint Louis Public Schools has been declining as a growing number of people are moving out of the city or choosing to send their children to charter schools.

That puts tremendous financial strain on the school system. Average daily attendance primarily determines school funding, according to the Missouri Department of Elementary and Secondary Education. And the board of education is considering a proposal to close half of its schools for the 2026-2027 school year.

Boleyjack blames steep budget cuts for lax vaccination enforcement. She said that some administrators allow noncompliant children to stay in school to keep enrollment up to be eligible for tax money.

“They got to get their dollars. So they’re going to let in students who may not be completely compliant,” she said. “I don’t agree with it, but that’s what it is.”