Measles vaccination rates in Colorado are lagging
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Most Colorado counties don't meet the herd immunity threshold for measles, with vaccination rates for kindergarteners below the 95% mark, per new data collected and analyzed by the Washington Post.
Why it matters: The state's measles cases are rising to historic levels, leaving local communities vulnerable to a virus public health officials say is preventable.
By the numbers: Colorado recorded 36 cases in 2025, according to state health department data, including in large counties like Denver, Arapahoe and El Paso.
Stunning stat: Only seven of Colorado's 64 counties meet the herd immunity threshold, data shows.
- That threshold is widely considered necessary to contain the virus' spread.
The big picture: Colorado isn't an outlier. The battle against infectious diseases like the flu and measles has taken a hit with sinking vaccination rates for children in many parts of the U.S.
- The decline has set the U.S. up to lose its coveted elimination status for the first time in decades.
What's next: Federal health policy is shifting.
- The Trump administration this week overhauled the childhood vaccination schedule by cutting recommended shots to 11, though the recommended list still includes a measles shot for kids.
Go deeper: Where vaccination rates declined the most, by county