Sen. Bernie Sanders on Thursday unveiled a collection of internal Health and Human Services emails that he says show HHS Secretary Robert F. Kennedy Jr. intervening in the Centers for Disease Control and Prevention’s vaccine policies and communications.

According to Sanders, the emails suggest Kennedy directed the CDC’s vaccine advisory committee to limit vaccine availability, authorized researchers to examine confidential information in an effort to support the disputed claim that vaccines cause autism, and altered federal COVID-19 vaccine recommendations without consulting the CDC.

Another set of emails indicates that Kennedy’s then-chief of staff, Matthew Buckham, contacted then-CDC Director Susan Monarez in August 2025, instructing that major agency actions undergo political oversight before being finalized.

The email stated there was a need for a “political review of major decisions at CDC … to ensure that [the Immediate Office of the Secretary] and the CDC political leadership all have eyes on the decisions for approval/changes before they go into effect.”

Sanders said Monarez was dismissed less than a week later after refusing to endorse recommendations issued by the CDC’s Advisory Committee on Immunization Practices.

In a statement, Sanders called Monarez’s termination “outrageous,” arguing that she lost her position “for her commitment to public health and vaccines.” The Vermont senator urged Congress to conduct a bipartisan investigation into the firing and renewed his call for Kennedy to step down.

The emails also appear to show that Kennedy ordered the cancellation of federal influenza vaccine advertising campaigns. In one message, a CDC employee informed her supervisor that Andrew Nixon, HHS communications director, had instructed her to immediately halt all flu vaccine promotional efforts.

“He said this request came directly from the Secretary,” the staffer wrote. “I noted that these have been paid for and are in flight and he acknowledged and asked that we work right away on things that are on social/online, magazines, and then will eventually need to do items that may be on bus stops or benches (if it includes those type of things).”

A separate email from Nixon, which Sanders also released, reiterated that the directive “was a direct ask from Secretary Kennedy.”

Sanders said the emails were provided to the Senate committee by Dr. Debra Houry, the CDC’s former chief medical officer.

The senator, who serves as the ranking Democrat on the Senate Health, Education, Labor and Pensions Committee, has repeatedly urged Chairman Sen. Bill Cassidy (R-La.) to hold hearings examining Kennedy’s statements about vaccines. Kennedy was a longtime vaccine skeptic before being nominated by President Trump to lead HHS, and Sanders has accused him of spreading misinformation while serving as secretary.

In an April letter to Cassidy, Sanders wrote, “The reality is that since Secretary Kennedy has been in office, he has continued his longstanding crusade against vaccines and his advocacy of conspiracy theories that vaccines cause autism — all of which have been repeatedly rejected by scientists,” Sanders wrote in his letter to Cassidy in April.