Rising Measles Cases Driven by Falling Vaccination, Not Illegal Immigration

Rep. Byron Donalds, a Republican from Florida who is running for governor, has blamed “rampant illegal immigration” during the Biden administration for measles outbreaks. But we found no link to illegal immigration in several recent large outbreaks, and infectious disease experts told us that the main driver of the cases is falling measles vaccination rates in the U.S.

Measles was eliminated in the U.S. in 2000, meaning there were no sustained outbreaks lasting more than a year. But since January 2025, cases have risen markedly, and the country’s elimination status is now in question. Last year, there were 2,289 confirmed cases — the highest number since 1991. As of Aug. 30, there have been 2,903 confirmed cases in 2026, already breaking 2025’s tally. 

Donalds weighed in on the cause of measles outbreaks during an Aug. 23 interview on CBS News’ “Face the Nation” in response to a question from host Margaret Brennan, who asked whether he would tell Florida parents to get their children vaccinated against the disease. “No, actually, my message to Floridians and, quite frankly, to Americans is that the reason why we have seen a measles outbreak in certain parts of the country is because of rampant illegal immigration into the United States from the previous administration,” Donalds replied. 

When Brennan asked him for evidence for this statement, Donalds referred to “the outbreaks in El Paso, Texas, in Southwest Florida, where I live, and many other parts where you know that you have a situation,” adding that people entering the country illegally “have not had that vaccination schedule.”