A new study found that measles vaccination rates in children have declined in most U.S. counties since before the COVID-19 pandemic, according to a research letter published June 2 in JAMA Network.  The analysis, conducted by researchers at Baltimore-based John Hopkins University, shows a national trend of decreasing vaccination rates for measles, mumps and rubella.

Here are four notes: 

Of the 2,066 counties examined across 33 states, 78% of those counties experienced a drop in MMR vaccination rates, CBS News reported June 2. Between the 2017-2018 school year and the 2023-2024 school year in those states, vaccination rates dropped from 93.92% to 91.6%.

California, Connecticut, Maine and New York saw increases in their average county-level vaccination rates, and the other states were

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