The chaos from the first day of a meeting of the federal vaccine committee appointed by Health Secretary Robert F. Kennedy Jr. bled into the second day, as the panel reversed one decision and indefinitely postponed a vote on a hepatitis B vaccine they had already deferred once.
On Friday morning, the committee voted not to allow a federal vaccine program to cover the cost of a combination vaccine that protects against measles, mumps, rubella and varicella, or chickenpox. This reversed a vote on Thursday to allow coverage, apparently because some members had misunderstood the way it was worded.
And the panelists said they felt unready to decide whether to limit the use of a vaccine for hepatitis B that is typically given to all newborns. Some said they still had questions about the vaccine’s safety, while others seemed relieved that the panel did not make what they saw as a rash decision that might harm children.
“We are more prudent when we are cautious,” Dr. Joseph Hibbeln, a neuroscientist formerly at the National Institutes of Health, said as he voted to table the vote.
Thursday’s session ended with the panel members at odds. A hot microphone caught one panelist calling another committee member “an idiot,” although it was unclear who was speaking.
Friday’s session, too, at times devolved into raised voices and sharp-toned remarks. Dr. Jason Goldman, a liaison to the committee from the American College of Physicians, accused the committee’s chair, Martin Kulldorff, of muting him.
“You want debate and discussion, but you’re muting people and silencing them,” Dr. Goldman said. “If you could respectfully tell the public how you are going to be analyzing all of these vaccine decisions, we can have confidence in this committee.”
Dr. Kulldorff retorted: “You made that comment before, and I responded to that comment in a very nice and polite manner.”
The committee’s decisions are of enormous importance. Most private insurers are required to cover the shots it recommends — although they may choose to cover those not recommended — and many state policies on vaccines are tied to the committee’s guidelines.
At least some members seemed aligned with Mr. Kennedy’s goal of making sweeping changes to routine childhood immunizations. Mr. Kennedy has maintained for years that children receive too many shots, and he has incorrectly claimed that the vaccines in use today were never properly tested.
The indecision of the panelists was a sign of the hurried way that Mr. Kennedy assembled the committee. Most of the panelists are first-time members, and their inexperience seemed to lead to the confusion that marred the meeting. About half of the committee members were appointed to the panel earlier this week.
On Thursday, the committee voted to rescind the M.M.R.V. vaccine’s use in children under 4. A second vote was on whether the Vaccines for Children program, which provides shots to about half of American children, should continue to cover the cost of the shot. The committee voted yes on Thursday and then reversed that decision on Friday, in another vote.
Such a contradiction was a first for the panel, called the Advisory Committee on Immunization Practices, as was the decision the next day to redo the vote.
Approving which shots the vaccine program should cover is a key function of the committee, but some members did not appear to know how their decision would affect coverage. Several members said Thursday that they were unclear what they were voting for. One abstained from the vote, citing his confusion as the reason.
The members themselves seemed uncomfortably aware of the optics.
The panelists have “enormous depth and knowledge” about vaccines, Dr. Kulldorff acknowledged on Friday, but they are “rookies” when it comes to how the A.C.I.P. committee typically makes decisions.
In June, Mr. Kennedy fired all 17 previous members of the committee, and appointed seven new members, many of whom are aligned with his vaccine skepticism. He announced another five members earlier this week. Members of the A.C.I.P. are typically vetted for months to years before they are invited to join.
Some medical organizations sharply criticized the committee’s skipping of the methods the A.C.I.P. has typically followed, with detailed discussions on how feasibile and acceptable the decision is, the cost-benefit ratio and equity concerns.
Instead, the panelists were “distracted” by small studies that raised safety concerns, said Dr. Amy Middleman, who heads pediatrics and adolescent medicine at Case Western Reserve University. She is a liaison to the committee from the Society for Adolescent Health and Medicine.
Every vaccine and drug carries risks, she said, but “the committee’s scientific challenge is to determine whether the benefits outweigh the risk.”
Public health experts who study hepatitis B said they were pleased that the committee postponed the vote on that vaccine.
“Tabling the vote is appropriate and a relief,” said Dr. Noele P. Nelson, a senior author on the current guidelines for the vaccine and a former leader of the C.D.C.’s hepatitis vaccines work group.
“This discussion should not be rushed and would benefit from a more comprehensive evaluation of the public health impact,” she said.
Babies are routinely immunized for hepatitis B within 24 hours after birth. The committee was scheduled to vote on whether the shot should instead be recommended only for those newborns whose mothers were known to be infected. Other babies, the motion said, should be immunized only after they are at least one month old.
Hepatitis B experts noted that the vaccine has nearly eliminated maternal transmission of the disease in the United States, slashing the incidence to fewer than 20 cases a year from about 20,000 a year before 1991, the experts said.
They said delaying the first dose of the vaccine would increase the risk to newborns because many cases in pregnant women are missed, despite a longstanding recommendation to test them routinely.
Infected women may also not be identified because of inaccurate results or because of problems reporting or interpreting the results.
“A universal birth dose recommendation is the only way to ensure we don’t miss vaccinating newborns exposed to this virus, including those whose mothers were not tested during pregnancy,” said Dr. John. W. Ward, director of the Coalition for Global Hepatitis Elimination and a former head of the C.D.C.’s viral hepatitis division.
Hepatitis B experts also questioned the panel’s focus on the vaccine’s safety, despite years of data from millions of babies showing that the shot is safe. Some committee members were also unhappy with the discourse.
The discussion about the hepatitis B vaccine’s potential harms was veering into “speculation,” Dr. Hibbeln said on Thursday, sounding frustrated. “We need data on real risks and benefits.”
The committee is scheduled to vote on Covid-19 vaccines later on Friday and is expected to restrict access to those shots.
