Health and Human Services Secretary Robert F. Kennedy Jr. doubled down on false claims about vaccines during his Senate testimony on Wednesday, as senators grilled him on his sweeping changes to immunization policy and federal health agencies.

Kennedy said he supports a statement made by a newly appointed member of a key government vaccine panel that mRNA vaccines pose a dangerous risk to people. Numerous studies have demonstrated that shots using mRNA technology, including Covid vaccines from Pfizer and Moderna, are safe and effective, and serious side effects have happened in extremely rare cases.

Sen. Michael Bennet, D-Colo., noted that the committee member Dr. Retsef Levi has said that evidence is mounting that mRNA vaccines cause “serious harm, including death, especially among young people,” apparently referring to a post pinned on Levi’s X account. Kennedy appointed Levi to the Advisory Committee on Immunization Practices, which advises the Centers for Disease Control and Prevention on vaccine recommendations and insurance coverage.

Kennedy said he wasn’t aware of Levi’s comments, but added, “I agree with it.”

Kennedy’s comments before the Senate Finance Committee come after he repeatedly promised the panel in January that he would do nothing as HHS secretary that makes it more difficult or discourages people from taking vaccines. Since then, he has canceled funding for mRNA shot development and made other vaccine policy changes that could limit access to immunizations, including gutting the CDC vaccine panel and dropping Covid shot recommendations for certain groups.

His comments also follows a leadership shakeup at the Centers for Disease Control and Prevention. The White House last week fired CDC Director Susan Monarez, and four senior agency officials resigned shortly after, with some of them citing the politicization of the agency and a threat to public health. In an opinion piece on Thursday, Monarez accused Kennedy of “a deliberate effort to weaken America’s public-health system and vaccine protections.”

Kennedy touted skepticism around Covid vaccines, despite evidence of their safety and effectiveness. 

“We were told again and again the vaccines would prevent transmission, they prevent infection. It wasn’t true. They knew it from the start,” Kennedy said.  

He also said he does not know how many people died of Covid and whether the vaccines prevented deaths from the virus.

“I would like to see the data and talk about the data,” Kennedy said.

But data is readily available from dozens of studies. One paper in August estimates that Covid vaccines saved more than 2 million lives, mostly among older adults, worldwide between 2020 and October 2024. 

The CDC website also says that Covid vaccines from the 2023 to 2024 season reduced the risk of severe illness from Covid by almost 70% in the first two months after vaccination in adults ages 18 and older, with protection gradually decreasing over time.

Those shots also decreased the risk of hospitalization due to Covid by around 50% in the first two months of vaccination in that same population. The Covid vaccines showed similar benefits in older adults.

Kennedy also defended his decision to fire all 17 previous members of the CDC vaccine panel, saying he didn’t politicize the committee.

“What we did is we got rid of the conflicts of interest. … We depoliticized and put great scientists on it from a very diverse group,” the HHS secretary said. “They are very, very pro-vaccine.”

But a new analysis published last month from USC researchers found that conflicts of interest on that panel had been at “historic lows for years” before Kennedy restacked it with new members, some of whom are widely known vaccine critics.