Vials of measles, mumps and rubella vaccine. (Justin Sullivan/Getty Images)

More than 350 organizations, including leading U.S. medical, advocacy and professional organizations, have sent a letter to President Trump expressing their “unequivocal support for the safety of vaccines.”

The effort, organized by the American Academy of Pediatrics, reflects the growing alarm among a wide array of groups over Trump’s embrace of discredited claims about vaccine safety. After a meeting in January with Robert F. Kennedy Jr., a proponent of the debunked theory that vaccines cause autism, a Trump spokeswoman said he was considering creation of a commission on autism.

“Vaccines protect the health of children and adults and save lives,” the letter opens. “Vaccines have been part of the fabric of our society for decades and are one of the most significant medical innovations of our time.”

It continues: “Claims that vaccines are unsafe when administered according to expert recommendations have been disproven by a robust body of medical literature.”

The letter was sent to Trump on Tuesday. Organizations that signed on represent families, providers, researchers, patients and consumers. They include the American Medical Association, the advocacy group Autism Speaks and major children’s and disability groups such as the Children’s Defense Fund, Easter Seals and the March of Dimes.

Following their meeting last month, Kennedy said that he and Trump had discussed creation of a vaccine commission, which he would chair. The Centers for Disease Control and Prevention already has a well-established expert panel, the Advisory Committee on Immunization Practices, which follows a scientifically rigorous and open process to evaluate all aspects of vaccine safety.

The letter calls vaccines the safest and most cost-effective way of preventing disease, disability and death. It notes that the United States is still experiencing outbreaks of vaccine-preventable illness, disability and death, such as the 2014-2015 measles outbreak that began at Disneyland and the sharp spike of pertussis, or whooping cough, in 2012.

The organizations wrote that they would welcome a meeting with Trump “to share the robust, extensive, scientific evidence” supporting vaccine safety and effectiveness. After just over a page of text, the letter continues for 26 additional pages to list all the national and state-based groups that signed as well as a summary of more than 40 studies on vaccine safety.

Here is the letter in full:

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