Robert F. Kennedy Jr.'s personal attorney previously lobbied the Food and Drug Administration to revoke its approval of the polio vaccine, highlighting an influential Kennedy ally who, sources tell ABC News, has been helping interview candidates for top health jobs in the incoming Trump administration.
The matter could be something RFK Jr. gets questioned about when he goes to Capitol Hill next week to meet with senators considering whether to confirm him as health and human services secretary..
Aaron Siri, a partner at the law firm Siri & Glimstad, has long fought against the prevalence of vaccines. He has also filed petitions seeking to pause the distribution of other vaccines, including Hepatitis B, and to revoke the emergency-use authorization of COVID-19 vaccines.
The 2022 polio petition was made on behalf of one of Siri's clients, the Informed Consent Action Network (ICAN), a group founded by Del Bigtree, another close Kennedy ally also involved in health-related transition matters, according to sources.
"Petitioner requests that the FDA withdraw or suspend the approval for [the polio vaccine] for infants, toddlers, and children until a properly controlled and properly powered double-blind trial of sufficient duration is conducted to assess the safety of this product," Siri wrote.
The New York Times reported on the petition earlier Friday.
Siri did not immediately respond to an ABC News request for comment.
Kennedy, meanwhile, did not respond to written questions about whether he agrees with revoking approval of the polio vaccine, or if, as health and human services secretary, he would intervene in an FDA review of Siri's petitions.
The polio vaccine available in the United States is recommended for children and three doses offer at least 99% protection against severe disease, including paralysis, according to the CDC. Side effects are usually mild and go away on their own, the agency notes, and the vaccine has not been known to cause serious problems.
Since the late 1980s, global polio cases have decreased by more than 99% alongside increased vaccination efforts to eradicate the disease, from an estimated 350,000 cases to just six reported in 2021, according to the World Health Organization. The efforts have allowed an estimated 20 million people to walk today who would have otherwise been paralyzed and saved more than 1.5 million lives, according to the CDC.
The polio vaccine has been a part of routine childhood schedule for decades, and federal health officials utilize multiple systems to monitor for vaccine safety. Polio can cause lifelong paralysis and up to 10% of children who have paralysis from polio die, as the virus affects the muscles that allow them to breathe, the CDC notes.
Senate Minority Leader Mitch McConnell, a polio survivor, said in a statement provided to ABC News that any efforts to undermine public confidence in proven cures is not only uninformed, but also dangerous.
"Like millions of families before them, my parents knew the pain and fear of watching their child struggle with the life-altering diagnosis of polio," he said. "From the age of two, normal life without paralysis was only possible for me because of the miraculous combination of modern medicine and a mother's love. But for millions who came after me, the real miracle was the saving power of the polio vaccine.
"For decades, I have been proud to work with devoted advocates -- from Rotary International to the Gates Foundation -- and use my platform in public life to champion the pursuit of cures for further generations. I have never flinched from confronting specious disinformation that threatens the advance of lifesaving medical progress, and I will not today.
"The polio vaccine has saved millions of lives and held out the promise of eradicating a terrible disease. Efforts to undermine public confidence in proven cures are not just uninformed -- they're dangerous," he continued. "Anyone seeking the Senate's consent to serve in the incoming Administration would do well to steer clear of even the appearance of association with such efforts."
Senate Majority Leader Chuck Schumer is also calling on RFK Jr. to "state his position" on the matter.
"This would undoubtedly make America sick again. It's outrageous and dangerous for people in the Trump Transition to try and get rid of the polio vaccine that has virtually eradicated polio in America and saved millions of lives. RFK Jr. must state his position on this," Schumer said in an online post.
ABC News' Youri Benadjaoud contributed to this report.