Aaron Siri, who represented Kennedy during his presidential campaign, is now reviewing candidates for top jobs in the Health and Human Services Department under Trump 2.0, the New York Times reported. But before the campaign, Siri had asked the Food and Drug Administration to revoke its approval of a single-antigen polio vaccine, according to the Times. 

His petition was filed in 2022 on behalf of the Informed Consent Action Network, the publication reported. The Informed Consent Action Network is a nonprofit that appears to be anti-vaccine. It was founded by Del Bigtree, who was the communications director for Kennedy’s campaign.

That wasn’t a sole occurrence either. Siri, on behalf of the ICAN, has asked the government to revoke its approval of hepatitis B vaccines and filed a petition seeking to pause the distribution of 13 other vaccines if the FDA couldn’t disclose the correct amount of aluminum they contained. He has also challenged coronavirus vaccine mandates, and in some cases succeeded.

The 2022 petition takes aim at IPOL and its use for children. IPOL is a single-antigen vaccine, meaning it protects against a single disease—polio. The petition claims the clinical trials for IPOL didn’t include a control group and only assessed safety for up to three days after injection. Therefore, the trials did not comply with requirements necessary to prove it was safe prior to licensure, according to the petition. 

Siri’s law firm, Siri & Glimstad, pointed out that even if its petition was granted, people could still be vaccinated against polio via five other licensed vaccines. They include combination vaccines Pentacel, Pediarix, Kinrix, VAXELIS, and Quadracel that provide immunization against other diseases as well, according to the Centers for Disease Control and Prevention.

There’s a long-standing debate in the medical world about whether it is ethical to use placebos in clinical trials. Some say if a proven therapy exists, a placebo shouldn’t be used—and others say placebo use is crucial to proving efficacy and safety. Polio is a highly infectious disease that can be deadly. 

Before Jonas Salk created the first successful vaccine, polio killed or paralyzed over half a million people every year around the world, according to the World Health Organization. That vaccine came in the 1950s, and annual cases dropped from 58,000 to just 161 by 1961. 

The vaccine named in the petition is made by Sanofi, and its head of vaccines for North America told the Times more than 280 million people had received the vaccine worldwide and it has been subject to over 300 studies with as long as six months of safety follow-up. 

The Kennedy team did not immediately respond to Fortune’s request for comment. Siri told the Times the petitions were filed on behalf of clients; and a spokeswoman for Kennedy said Siri has been advising him but has not discussed his petitions with any of the health nominees. “Mr. Kennedy has long said that he wants transparency in vaccines and to give people choice,” the spokeswoman told the outlet.

Meanwhile, Siri has tagged along at Mar-a-Lago, working with Kennedy on filling jobs at HHS. The two have asked applicants about their views on vaccines, a person familiar told the Times. Kennedy has reportedly shown interest in Siri being general counsel for HHS. But Siri thinks he’ll have more influence from the outside, per the Times. His law firm works on vaccine cases.

To be clear, Kennedy has recently said, “I’m not going to take away anybody’s vaccines.” According to the Times, Siri has said as much, too. “You want to get the vaccine—it’s America, a free country,” he once said. Nonetheless, if Kennedy is confirmed, he would oversee the FDA. 

Interestingly enough, during an interview earlier this month, President-elect Trump said: “The polio vaccine is the greatest thing. If somebody told me to get rid of the polio vaccine, they’re going to have to work real hard to convince me.” Separately, in his interview for Time’s Person of the Year, Trump said his administration could get rid of some vaccines, if he thinks they’re dangerous or not beneficial, but that they’d do serious testing.  

Two prominent Democrats, Sen. Elizabeth Warren and former Secretary of State and presidential nominee Hillary Clinton, took the opportunity to criticize Trump’s pick. Warren said: “Say goodbye to your smile and say hello to polio – that’s what’s on the horizon if Robert F. Kennedy Jr. becomes the Secretary of Health and Human Services.” And Clinton said: “I think Trump voters may be surprised to learn they voted to make polio great again.”

Clarification, Dec. 16, 2024: This article has been updated to clarify the availability of combination vaccines that vaccinate people against polio along with other diseases.