Measles Vaccination Rates Are Plummeting Across the U.S.

Childhood vaccination charges in opposition to measles, mumps, and rubella have been declining in a lot of the U.S. because the begin of the COVID-19 pandemic, a brand new examine has discovered.

The examine, which was revealed in JAMA on June 2, analyzed measles, mumps, and rubella (MMR) vaccination charges by county the place knowledge have been out there. Researchers at Johns Hopkins College collected county-level knowledge on MMR vaccination charges for kindergarteners from every state’s well being division web site for the college years earlier than the pandemic (2017-2018) and after (2023-2024). In states the place that knowledge weren’t out there, researchers analyzed essentially the most comparable knowledge as a substitute.

Of the two,066 counties in 33 states that researchers analyzed, 78% of them reported a decline in vaccination charges. Researchers discovered that the county-level imply vaccination fee decreased from nearly 94% earlier than the pandemic to about 91% after the pandemic—falling effectively beneath what public-health consultants usually take into account to be the brink for herd immunity in opposition to measles of about 95%.

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Lauren Gardner, senior writer of the examine and director of Johns Hopkins College’s Middle for Programs Science and Engineering, says the aim of this analysis was to get a “extra complete, larger decision understanding of the vaccination panorama” within the nation.

The U.S. Facilities for Illness Management and Prevention (CDC) “has national- and state-level knowledge, however we all know that vaccination patterns can fluctuate considerably inside a state and even at a better decision than that throughout communities, inside even the county,” Gardner says. For locations with a low vaccination fee, “if measles will get launched into these areas, there’s extra prone to be an outbreak. And that’s what we’re seeing.”

As of Could 29, a complete of 1,088 confirmed measles instances have been reported by 33 jurisdictions within the U.S., in keeping with the CDC. Of these instances, 96% have been in individuals who have been both unvaccinated or whose vaccination standing was unknown. To this point in 2025, there have been 14 reported outbreaks and three folks confirmed to have died of measles-related issues, all of whom have been unvaccinated. Earlier than this yr, the final confirmed measles-related demise within the nation occurred in 2015.

Getting vaccinated is the easiest way to be protected in opposition to measles. The MMR vaccine is each protected and efficient, and the CDC has stated that most individuals who get it is going to be protected in opposition to measles for all times.

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The brand new examine discovered that solely 4 of the 33 states that researchers analyzed—California, Connecticut, Maine, and New York—reported an increase within the median county-level vaccination charges. Researchers didn’t examine the causes behind disparate charges, and Gardner says that many components—together with the pandemic’s influence on entry to well being care, completely different populations, the standard of reported knowledge, and vaccine hesitancy—play a task in a neighborhood’s vaccination charges. However she additionally notes that the 4 states that reported a rise within the measles vaccination fee are among the many few that don’t permit non-medical exemptions for college immunization necessities, such because the MMR vaccine.