Childhood vaccination rates against measles fell in the years after the COVID-19 pandemic in nearly 80% of the more than 2,000 U.S. counties with available data — including in states that are battling outbreaks this year.
A Johns Hopkins University study, published in JAMA this week, illustrates where more vulnerable communities are located. The results mirror trends established at state and national levels: Routine childhood vaccination rates are dropping.
''When you look at the state level or national level ... you really don't see those drastic drops. Those are there. They're real and they're really problematic,'' said Lauren Gardner, an expert in infectious disease modeling at Johns Hopkins University who is the paper's senior author. Gardner also built the university's COVID-19 database.
Most of the measles cases in the U.S. this year — 1,088 nationally as of Friday — are in unvaccinated people. It has been spreading among communities due to international and domestic travel. Three people have died from measles during this year's outbreaks, and 2025 is inching closer to becoming the worst for measles in more than three decades.
Measles was eliminated in the U.S. in 2000, and the vaccine is safe and highly effective. Public schools nationwide require two doses of the measles, mumps and rubella vaccine before kindergarten, but the number of children with non-medical exemptions from those requirements hit an all-time high in the 2023-2024 school year. Health experts say community-level vaccination needs to be at 95% or higher to prevent outbreaks.
The Johns Hopkins study looked at 2,066 counties across 33 states, comparing kindergarten vaccination rates averaged over school years from 2017-2020 to averages from 2022-2024. Where kindergarten data wasn't available, the researchers used a comparable rate.
Here's what it looks like in counties where there have been outbreaks this year, including in Texas counties that are the epicenter of measles.
Texas
