Vaccine advisers appointed by Health Secretary Robert F. Kennedy Jr. are on the verge of ending the practice of vaccinating all newborns against hepatitis B, which would represent a betrayal of a key Republican senator.

Sen. Bill Cassidy (R-LA), who expressed skepticism about Kennedy's nomination until receiving assurances about his stance on vaccines, has said he's "very concerned" about possible changes to the hepatitis B vaccine schedule for infants.

But the health secretary's allies plan a vote to do just that, reported the Washington Post.

"Kirk Milhoan, a pediatric cardiologist and critic of coronavirus vaccination who recently took over as chair of the influential vaccine panel, said members meeting Thursday and Friday are broadly scrutinizing vaccines recommended for children," the Post reported.

The panel will discuss the timing of vaccines and ingredients as Kennedy and his allies reshape immunization policy, which has for decades called for administering vaccines at set milestones during childhood and adolescence, but Kennedy has claimed links between vaccines and autism, chronic disease, and food allergies that have been refuted by researchers and medical associations.

"The members of the Advisory Committee on Immunization Practices are preparing to make their most significant change to the childhood vaccine schedule yet since Kennedy purged the panel and replaced members with experts who have largely been critical of public health vaccination practices," the Post reported.

Cassidy has previously called for the postponement of the panel's September meeting after Kennedy said he was "retiring" all 17 members and replacing them with his own choices, and the Louisiana Republican has strongly recommended hepatitis B vaccine doses at birth after witnessing their effectiveness as a physician whose medical practice focused on that preventable illness.

"The vaccine is safe. It has been established," Cassidy said. "This is policy by people who don't understand the epidemiology of hepatitis B, or who have grown comfortable with the fact that we've been so successful with our recommendation that now the incidence of hepatitis B is so low, they feel like we can rest on our laurels."