Chicago – September 29, 2025
The vast majority of counties across the United States are experiencing declining rates of childhood vaccination and have been for years, according to an NBC News data investigation, the most comprehensive analysis of vaccinations and school exemptions to date.
This six-month investigation, done in collaboration with Stanford University, gathered massive amounts of data from state governments and archives of public records reaching back years or decades. The data focused on core childhood vaccines that, together, regard someone to be “up to date” on immunizations; these are the measles, mumps, rubella, polio, whooping cough and diphtheria shots.
With the help of infectious disease researchers at Stanford, NBC News filed scores of requests for documents, including materials obtained under the Freedom of Information Act, and wrestled different types of data into a standardized format to map and compare rates across thousands of counties.
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, 67% of counties and jurisdictions now have immunization rates below 95% — the level of herd immunity doctors say is needed to protect against an outbreak.
“As childhood vaccination rates fall, we’ll see more diseases like measles,” Dr. Sean O’Leary, an infectious diseases expert with the American Academy of Pediatrics, said about the findings. “And we’ll see more children die — tragically — from diseases that are essentially entirely preventable.”
St. Louis offers a window into the striking findings.
