ISTANBUL

The majority of the US counties have been experiencing declining childhood vaccination rates for years, according to a media report on Tuesday.

This finding came in a six-month investigation by NBC, conducted in partnership with Stanford University, which compiled extensive data from state governments and public record archives spanning years or even decades.

A large portion of the US currently lacks the baseline immunity that health experts say is essential to prevent the spread of measles, a disease once nearly eradicated, according to one crucial finding of the investigation.

Since 2019, over three-fourths of US counties and jurisdictions have seen significant drops in childhood vaccination rates, ranging from under 1 percentage point to over 40 percentage points, the analysis found.

Nationwide, vaccine exemptions for schoolchildren are growing, with exemption rates more than doubling in up to 53% of counties and jurisdictions since their first year of data collection.

The report comes on the same week that Florida’s governor, Ron DeSantis, announced that the state is eliminating all vaccine requirements for school attendance, in a radical departure from long-standing US public health policy.

The report added that in states reporting measles-mumps-rubella (MMR) vaccine data, 68% of counties and jurisdictions now fall below 95% – the herd immunity threshold doctors say is required to prevent outbreaks.

St. Louis, Missouri serves as a case in point for the investigation's results. The percentage of children entering kindergarten with all state-required vaccines in the city has dropped from 91.6% in the 2010–2011 school year to 75.9% in 2024–2025.

Also, the rate of families requesting vaccine exemptions for their children increased from 0.3% in 2010 to 3.4% in the most recent school year. Children in Missouri may receive vaccine exemptions for either medical or religious reasons.

The report also comes as Robert F. Kennedy Jr., the US health and human services secretary, is under fire for bringing his vaccine skepticism to public policy by denying the proven efficacy of vaccines and appointing vaccine doubters to key positions.