Fact Check: Did illegal immigration during the Biden administration cause U.S. measles outbreaks?

Media Bias Fact Check (MBFC) publishes daily vetted fact checks from verified IFCN-approved sources. Each claim is independently reviewed for accuracy and context.


Claimant: Byron Donalds (R)


Claim: “Rampant illegal immigration” during the Biden administration is the cause of “a measles outbreak in certain parts of the country.”


Rating: BLATANT LIE


Explanation: Experts identified declining MMR vaccination rates in the United States as the primary driver of measles outbreaks. No data were found linking immigrants living in the country illegally to those outbreaks.


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Date: 09/01/2026


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Last Updated on September 1, 2026 by Media Bias Fact Check