Donald Trump’s executive order altering the federal guidance for childhood vaccines has been blasted as “dangerous” by the American Academy of Pediatrics and criticized by a Republican senator.

Trump’s called Monday’s order a “ historic step in our mission to make America healthy again” as he signed it in the Oval Office, while making unfounded claims about the non-existent link between vaccines and autism.

“My administration is recognizing gold standard childhood vaccine recommendations for only 11 core vaccinations against the most serious and dangerous diseases,” said Trump, who added that the measles, mumps and rubella vaccine that has been used since 1971 would once again be broken up into three separate vaccines despite the lack of any such separate vaccines on the current market.

Despite Trump’s order, it is the states, not the federal government, that have the authority to require vaccinations for schoolchildren.

Dr. Andrew Racine, president of the American Academy of Pediatrics, said that Trump’s announcement spread fear and confusion in an area where “there doesn’t need to be any of that.”

“Science about vaccines and their efficacy has not changed,” he said. “The distribution of viruses and other pathogens in our environment has not changed. Children in this country have not changed in the last 48 hours.”

Sen. Bill Cassidy, the Republican chair of the Senate health committee who lost his reelection bid after Trump backed his opponent, also slammed the executive order in a social media post, saying vaccines are safe and do not cause autism.

“I’m a doctor. This executive order is wrong. The President does not have the expertise to make these changes,” he posted.

“Vaccines are overwhelmingly safe. Vaccines are effective. Vaccines DO NOT cause autism. Breaking up vaccines will mean children have to get more shots to get the same protection, not fewer shots. It will increase hesitancy and make children less safe. Parents should listen to their child’s pediatrician about vaccines rather than listening to an inaccurate executive order. This is so wrong.”

Trump also announced that vaccines for Covid-19, influenza and hepatitis B would no longer be recommended, despite warnings from health experts that not vaccinating against the liver disease could give rise to an epidemic of liver cancer in unvaccinated children infected with the virus.

“Parents can still choose to give their children all of the vaccinations if they wish. It’s up to the parents. We’re making recommendations that are strong, but it’s up to the parents if they wish, and they will be covered by insurance,” he said.

Kush Desai, a Trump spokesperson, told The Associated Press that the president is “one of countless parents who have voiced questions and concerns about the combined MMR vaccine” and said the plan to develop single-disease vaccines would “give parents more options on timing and frequency for their children,” ultimately increasing vaccine uptake.

The Independent has reached out to the Department of Health and Human Services for comment.

The Associated Press contributed to this report.