The move comes as fears rise about Kennedy’s past vaccine skepticism, which he will be able to take action on if the Senate confirms him to lead the HHS.

Kennedy said he doesn’t want to take away vaccines for people to use but wants to improve the science on vaccine safety so that people can make “informed choices.”

Aaron Siri, the lawyer, is also petitioning the Food and Drug Administration to suspend or withdraw approval of the hepatitis B vaccine, along with asking to “pause distribution” of 13 other vaccines. Those include combination products that cover tetanus, diphtheria, polio, and hepatitis A.

Siri is doing so until their makers disclose the use of aluminum in the products, which has been associated with an increase in asthma cases.

He also stated he only files petitions on behalf of clients, but it’s unknown how many or which petitions could have been asked for by Kennedy. A spokeswoman for Kennedy told the New York Times they have not discussed the petitions and that Siri is merely advising him.

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

If a vaccine such as the polio vaccine comes off the market, it could have dangerous consequences. The disease is crippling and has no cure. The virus killed thousands of people in the United States before vaccine doses could be distributed and permanently disabled many survivors.

President-elect Donald Trump has had his share of vaccine skepticism in the past but admitted the polio shot “is the greatest thing.”

“The polio vaccine is the greatest thing,” Trump said last week. “If someone told me, ‘Get rid of the polio vaccine,’ they’re going to have to work really hard to convince me.”

Kennedy likely has a steep hill to climb to be confirmed, but if he is, Siri will help pick the health officials alongside him. Kennedy has praised Siri, saying, “There’s nobody who’s been a greater asset to the medical freedom movement than him.”

Some have credited Siri for his vaccine skepticism. Dr. Daniel Salmon, director of the Institute for Vaccine Safety at the Johns Hopkins Bloomberg School of Public Health, said Siri raises “points that are worthy of exploration,” such as his concern about the safety of aluminum in vaccines.

“There are issues that he raises, such as this one, that really deserve to be studied carefully,” Salmon said. “But it’s got to be done carefully — it’s hard to do.”