A key legal adviser to Robert Kennedy Jr., Donald Trump’s nominee for health secretary, is at the center of efforts to get federal drug regulators to revoke approval of polio and hepatitis B vaccines and suspend distribution of 13 to block other important vaccines.

Aaron Siri, a lawyer who helped Kennedy pick top health officials as part of the Trump transition process, is deeply enmeshed in the long-running effort to force the U.S. Food and Drug Administration (FDA) to withdraw a number of vaccines , which have saved the lives and health of millions of Americans.

Siri sat next to Kennedy in interviews asking candidates for top health care positions where they stand on vaccines, The New York Times reported Friday.

Kennedy, a leading vaccine skeptic, has insisted he has no plans to revoke vaccinations if he is confirmed by the U.S. Senate to be health secretary. However, his close ties to Siri raise concerns about the intentions of the new Trump administration, given the lawyer’s close ties to the anti-vaccination movement.

Siri works closely with the Informed Consent Action Network (Ican), a “medical freedom” nonprofit founded by Del Bigtree that has long waged war on vaccines, including as a producer of the anti-vaccine documentary “Vaxxed.” The New York Times report states that Siri filed the 2022 petition on behalf of ICAN asking the FDA to revoke approval of the polio vaccine.

The poliovirus, the causative agent of a disease once most feared by Americans, has been eliminated from the country by the United States through polio vaccines. The federal Centers for Disease Control and Prevention notes that the best way to prevent a recurrence of the disease and keep people safe is through vaccination.

Not only has Siri been involved in lawsuits calling for the withdrawal or suspension of the polio and hepatitis B vaccines, but he has also asked the FDA for a “suspension of distribution” of 13 other vaccines, according to the Times.

Trump said this week that Kennedy could investigate vaccines for an alleged link to autism. The remark to NBC suggests that his choice for health secretary may be based on the conspiracy theory that there is a link between childhood vaccinations and autism, which has been thoroughly debunked but is repeatedly promoted by Kennedy.

Kennedy spokeswoman Katie Miller confirmed to the Times that Siri had advised Kennedy, but said his vaccination requests had not been discussed.

“Mr. Kennedy has long said he wants transparency around vaccines and wants to give people choice,” she said.