President Donald Trump signed an executive order on Monday directing federal agencies to review and potentially scale back the number of vaccinations recommended for American children.

The move follows years of false claims by Trump about a link between childhood vaccines and autism, a theory that has been thoroughly debunked by the scientific community.

Health experts and medical organizations have consistently rejected the notion that vaccines cause autism, citing extensive research showing no such connection. The Centers for Disease Control and Prevention maintains that vaccines are safe and crucial for preventing serious diseases.

The executive order comes as the U.S. faces ongoing measles outbreaks and efforts to increase vaccination rates. Robert F. Kennedy Jr., a prominent vaccine skeptic, has been appointed to advise on the review process, raising concerns among public health officials.

Medical professionals worry the order could undermine public confidence in vaccines and lead to decreased immunization rates, potentially sparking preventable disease outbreaks.