The turmoil at the Centers for Disease Control and Prevention asHealth and Human Services Secretary Robert F. Kennedy Jr.pushed out the directorafter clashing over his approach to vaccines has generated bipartisan concern and put a spotlight on a key senator who was instrumental in Kennedy securing his job. CDC DirectorSusan Monarez was fired followinga dispute with Kennedy over vaccination policy. After Monarez's termination, resignation letters followed on Aug. 27 from CDC Chief Medical Officer Debra Houry and top officials for immunization and contagious diseases. Sen. Bill Cassidy, R-Louisiana, responded with asocial media poston Aug. 27 saying, "These high profile departures will require oversight" by a Senate committee he chairs. More:Senator snaps back at RFK Jr. for linking antidepressants to Minnesota shooting The shakeup comes after Kennedy wascriticized for his mixed messagingon a measles outbreak, firing a vaccine advisory panel andcutting $500 million in funding for developing mRNA technology, which is used in the two most common COVID-19 vaccines. Cassidy hasspoken outabout some of Kennedy's moves, including slashing funding for mRNA research. A longtime vaccine skeptic, Kennedyin May withdrewa federal recommendation for COVID shots for pregnant women and healthy children and followed up in June byremoving all 17 membersof the CDC's expert vaccine panel. In addition to calling for oversight after the CDC shakeup, Cassidy alsosaid in a statementon Aug. 28 that the agency's vaccine advisory panel should indefinitely postpone a Sept. 18 meeting. Kennedy replaced the fired vaccine panel members with hand-picked advisers, including fellow anti-vaccine activists. "These decisions directly impact children's health and the meeting should not occur until significant oversight has been conducted," Cassidy said. Cassidy said "serious allegations" have been made about the panel's "membership, and lack of scientific process being followed." "If the meeting proceeds, any recommendations made should be rejected as lacking legitimacy given the seriousness of the allegations and the current turmoil in CDC leadership," he added. Yet some health experts believe Cassidy deserves blame for what's happening as a physician in an important leadership position who was concerned about Kennedy's vaccine views butvoted to confirm him anyway.As such, Cassidy needs to do more than oversight said Dr. Thomas Farley, the former top public health official in New York City and Philadelphia. "Cassidy now, I think, does bare some responsibility to stop (Kennedy) from causing more damage," Farley said, arguing Kennedy needs to be fired. Cassidy's office did not respond to a request for comment. A longtime environmental lawyer, Kennedy has no educational background in medicine or health care. He ran for president as an independent in 2024 but dropped out of the race and endorsed Trump. Among his most controversial statements that have been discredited:Antidepressants are relatedto school shootings,wi-fi causes cancer,fluoride in public water systems causes bone cancer and IQ loss, and COVID-19 was "ethnically targeted" to attack "Caucasians and Black people" while sparing "Ashkenazi Jews and Chinese" people. Cassidy was considered a key swing vote during the confirmation process in January.Kennedy's nomination advanced14-13 in the Senate Finance Committee with Cassidy's support. "I've been struggling with your nomination,"Cassidy bluntly told Kennedyduring the confirmation process. "Does a 71-year old man who spent decades criticizing vaccines… can he change his attitudes and approach now that he'll have the most important position influencing vaccine policy in the United States?" The Louisiana senator ultimately cast the decisive vote to move Kennedy's nomination forward in committee, and joined with every Republican other than Sen. Mitch McConnell, R-Kentucky, in voting on the Senate floor to confirm Kennedy as Health secretary. Cassidy saidin his floor speechthat Kennedy and members of the Trump administration reached out to reassure him "about their commitment to protecting the public health benefit of vaccination" and he received "assurances." The senator also promised to be on guard. "If Mr. Kennedy is confirmed, I will use my authority... to rebuff any attempts to remove the public's access to life-saving vaccines without ironclad, causational scientific evidence that can be defended before the mainstream scientific community and before Congress," Cassidy said. "I will carefully watch for any effort to wrongfully sow public fear about vaccines." Cassidy's role in the confirmation process is now being resurfaced as Kennedy works to reshape the CDC in ways that many medical professionals find alarming. Some Kennedy critics are pointing the finger at Cassidy for his confirmation vote. "Just one senator could have prevented most of this by not confirmingRFK, Jr.And in my view, Cassidy, as a physician, is really the one to blame!" Dr. Douglas Henley, the former executive vice president and CEO of the American Academy of Family Physicians,wrote on social mediaAug. 28 in response to another doctor criticizing Kennedy after the CDC resignations. Farley believes Cassidy was under significant political pressure to approve President Donald Trump's HHS pick. He is up for reelection in 2026 in a state Trump carried by 22 percentage points. "He gave in to that pressure, so that was a mistake that we all potentially could suffer from," said Farley, who once worked at the CDC and on a Louisiana vaccination effort with Cassidy before he was senator. "I hope he can figure out how to now fix that mistake." Monarez, a who has doctorate in microbiology andpreviously workedat the Department of Homeland Security, National Security Council and in the White House, was ousted less than one month after the Senate confirmed her to the role. Her attorneys said she was targeted because she "refused to rubber-stamp unscientific, reckless directives and fire dedicated health experts." Kennedysaid on Fox Newsthat the CDC "is in trouble, and we need to fix it, and we are fixing it." "And it may be that some people should not be working there anymore," he added. For Kennedy's critics, the past seven months have only confirmed their reservations about his fitness for the nation's top health job. Democrats have called for Kennedy's termination amid the CDC upheaval. Rep. Don Beyer, D-Virginia, called Kennedy a "kook" with "crackpot conspiracy theories" ina social media poston Aug. 28 and said if President Donald Trump doesn't fire him he will "bear the responsibility for the unnecessary and preventable illnesses and deaths that result." Contributing: Joey Garrison, Ben Adler, Reuters, Savannah Kuchar, Swapna Venugopal Ramaswamy This article originally appeared on USA TODAY:Cassidy voted for RFK Jr. Now he wants CDC 'oversight.'