In a combative hearing on Thursday, senators pushed Health and Human Services Secretary Robert F. Kennedy Jr. on the politically tenuous effort to curtail access to the same vaccine that President Donald Trump has touted as an extraordinary achievement.
In an exchange with Republican Sen. Bill Cassidy, who was instrumental to his confirmation six months ago, Kennedy was pushed to answer for the contrast of his policies with the legacy of Operation Warp Speed -- Trump's first-term success of rapidly developing COVID shots, which studies show saved millions of lives during the pandemic.
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"Mr. Secretary, do you agree with me that … the president deserves a Nobel Prize for Operation Warp Speed?" Cassidy, a longtime physician, questioned Kennedy. He lauded the vaccine for saving lives and reopening economies around the globe.
"Absolutely, senator," Kennedy responded.
Kennedy's response was "surprising," Cassidy said, given Kennedy's cancellation of$500 million in federally-funded mRNA vaccine funding and his past work as an attorney seeking to restrict access to the COVID vaccine.
"It just seems inconsistent that you would agree with me that the president deserves tremendous amount of credit for this," Cassidy said.
Sen. Bill Cassidy questions Secretary of Health and Human Services Robert F. Kennedy Jr., as he appears before the Senate Finance Committee, on Capitol Hill in Washington, Sept. 4, 2025.
AP Photo/Mark Schiefelbein
Kennedy responded that Operation Warp Speed was "genius" because it "got the vaccine to market that was perfectly matched to the virus at that time, when it was badly needed because there was low natural immunity and people were getting very badly injured by COVID."
But throughout the hearing, Kennedy reiterated his skepticism of the COVID vaccine. He said "there's no clinical data" supporting COVID vaccine recommendations for healthy people, defending recent changes that narrowed the Food and Drug Administration's approval to only people over 65 or younger people with underlying conditions.
Doctors and public health officials contend that vaccination significantly lowers the risk of severe COVID, even for young and healthy people.
Kennedy also refused to say during the hearing that more than one million Americans died from COVID -- a tragic point the U.S. surpassed in 2022 -- or that COVID vaccines helped to save millions of lives, which has been determined by dozens of studies. On both points, Kennedy argued that the publicly available data was insufficient.
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His views rankled other high-profile Republicans, including the second-most powerful senator in the GOP, Sen. John Barrasso.
Barrasso, a doctor, said he had "grown deeply concerned" since Kennedy took over HHS. Barrasso, like Cassidy, offered firm support for Operation Warp Speed, calling it "a model of American ingenuity and public-private partnership."
"I believe it saved many, many lives," Barrasso said.
Kennedy said he intended to restore trust in the Centers for Disease Control and Prevention and vaccines, pointing to low uptake for COVID shots.
President Donald Trump, seen reflected in a television screen, speaks about "Operation Warp Speed" in the Rose Garden at the White House, Nov 13, 2020 in Washington.
Jabin Botsford/The Washington Post via Getty Images
But the tension, spilling over into public view as Republican senators confronted a Trump-appointed Cabinet member, showed the growing discomfort with Kennedy's controversial stances and policy moves.
Trump himself has walked a fine line between defending his legacy and leaving open questions about the vaccines.
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In a recent meeting with his Cabinet secretaries, including Kennedy, Trump called Operation Warp Speed "one of the greatest achievements ever."
But as Kennedy continues to question the safety of the COVID vaccines -- including taking action as HHS secretary to limit who is recommended and approved to get the shot -- the president took to Truth Social, asking for answers from the vaccine companies.
"It is very important that the Drug Companies justify the success of their various Covid Drugs. Many people think they are a miracle that saved Millions of lives. Others disagree!" Trump wrote.
"They show me GREAT numbers and results, but they don't seem to be showing them to many others. I want them to show them NOW, to CDC and the public, and clear up this MESS, one way or the other!!!" the president added.
Kennedy and the CDC were "ripping themselves apart" looking for answers, Trump said, pushing the vaccine companies to provide more data.
President Donald Trump speaks during a dinner in the State Dinning Room of the White House, Sept. 4, 2025, in Washington.
Alex Brandon/AP
Both Pfizer and Moderna have issued their support for Trump's Operation Warp Speed -- with Pfizer even echoing Republicans who contend it's worthy of a Nobel Prize -- and pointed to hundreds of publicly available studies showing the vaccines are safe and effective.
"Since 2021, the real-world effectiveness and safety of the vaccines have been confirmed by governments and health systems around the world," Moderna said in a statement.
Trump says RFK Jr. 'means very well' after his Senate testimony on vaccine policy
Despite the concern from some key Republican senators, the White House quickly came to Kennedy's defense after Thursday's hearing. Vice President JD Vance attacked Democratic senators who criticized Kennedy, and White House press secretary Karoline Leavitt said the administration was "championing gold-standard science."
Trump, too, offered praise for Kennedy, but said he didn't watch the hearing himself.
The president told ABC News that Kennedy "means very well" and that he heard the secretary "did very well" on Capitol Hill.
Trump said Kennedy has "got a different take" and "we want to listen to all of those things." He added that Kennedy is not "your standard talk" in his vaccine views, but said, "I like the fact that he's different."