Sen. Rand Paul, R-Ky., clashed with Sen. Bernie Sanders, I-Vt., and former CDC Director Susan Monarez over recommending vaccines for infants on Wednesday.

The back-and-forth arose during a Senate hearing on Health and Human Servicies Secretary Robert F. Kennedy Jr.'s decision to oust Monarez last month. Monarez claims she was forced out for refusing to fire individuals responsible for the CDC's vaccine recommendations, arguing there is no scientific support for removing certain vaccines from the list.

Paul sought to turn the tables on the former official during his questioning.

"When we're discussing the science here, we have to discuss what is the science in favor of giving the vaccine to a 6-month-old, and what are the benefits from that? And there is no benefit of hospitalization or death. And then what would the risks of that vaccine be? We have large population studies of the risks of the vaccine in younger people," Paul said.

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"You won't fire the people who are saying we have to vaccinate our kids at six months of age. That's who you refused to fire," he pressed.

"That assertion is not commensurate with the experience that I had with the individuals who were identified to be fired," Monarez replied as Paul cut her off.

"Did any of the people you refused to fire," Paul began before Sanders then interjected himself: "She's about to answer the question."

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Paul then argued that "we should" remove recommendations that infants receive the COVID-19 vaccine and others that he said are not relevant for children.

"What is the medical reason to give a Hepatitis-B vaccine to a newborn whose mom has no Hepatitis?" Paul asked.

Sanders then interjected again as Paul spoke over Monarez, who did not directly answer the question.

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"You had your time Bernie, I've got mine," Paul said testily before turning back to Monarez. "What is the medical, scientific reason and proof for giving a newborn a Hepatitis-B vaccine if the mom is Hep-B negative?"

Monarez again refused to answer the question directly, and Paul argued that "the burden should be on you" to prove that vaccines recommended for infants are actually helpful.

"You want to make all kids take this? The burden is upon you," he said.