New rules approved by Health Secretary Robert F. Kennedy Jr. could blunt the impact of a federal judge’s order freezing the Centers for Disease Control and Prevention’s vaccine advisory committee and putting many of its decisions on hold, experts say.

The changes were posted online Thursday in a new charter for the Advisory Committee on Immunization Practices, or ACIP — the document that lays out how the panel is supposed to operate. The CDC is required to review and renew the charter every two years, although it rarely makes significant changes.

The charter was posted nearly a month after a Massachusetts federal judge, in a lawsuit brought by the American Academy of Pediatrics and several other medical organizations, halted Kennedy’s remade ACIP and reversed many of the vaccine policy changes the panel had made over the last year — a move that adds further confusion over vaccine policy in the U.S. The judge said the committee’s members, many of whom are critical of vaccines, appeared to be “distinctly unqualified” to serve on the panel. The Department of Health and Human Services hasn’t yet appealed the ruling, but it has 60 days to do so.

Kennedy’s new version of the charter, health policy experts say, broadens who can serve on the committee and what it focuses on, including vaccine injuries.

“The new ACIP charter postures itself as a sincere attempt to identify vaccine adverse events, but it manipulates the advisory committee into intensely focusing on vaccine harms,” said Lawrence Gostin, director of the O’Neill Institute for National and Global Health Law at Georgetown University.

The previous charter, which expired last week, said members should have expertise in vaccines and related fields. The updated version keeps that language but makes one notable addition, saying members can be knowledgeable about “recovery from serious vaccine injuries.”

That matters, said Dorit Reiss, a vaccine policy expert at the University of California Law San Francisco, because the judge’s ruling centers in part on whether Kennedy’s handpicked members had the right qualifications to serve. By widening the criteria, Kennedy may have more room to bring back some of the same members in a newly formed ACIP.

“The changes in the language suggest to me they have in mind some of the older members,” Reiss said, referring to panelists Kennedy previously selected. “They also probably want to bring some new people who are anti-vaccine who are not in the old cadre.”

The charter also shifts ACIP’s mission in subtle but important ways, according to Richard Hughes, the AAP’s attorney.

It puts more weight on vaccine safety and “gaps” in research on adverse events following vaccination.

It also adds outside liaison groups that have been skeptical of vaccines: the Association of American Physicians and Surgeons, Physicians for Informed Consent, the Independent Medical Alliance, and the Medical Academy of Pediatrics and Special Needs. In a statement Friday, Dr. Joseph Varon, the Independent Medical Alliance’s president, applauded its inclusion in the committee.

Aaron Siri, a lawyer who has joined Kennedy in litigation against vaccine makers and was a personal lawyer for Kennedy’s presidential campaign, said in an email that the new charter is “a good step toward having a committee that considers vaccine safety as well as efficacy. Children harmed by vaccines deserve the same protection as those potentially harmed by infectious disease.” He was not a member of the advisory group but gave a presentation to the panel in December on the childhood vaccination schedule that sparked outcry from public health experts. Last month, Siri petitioned Kennedy to update the charter to include language on vaccine injuries.

The new charter also no longer guarantees that ACIP’s recommendations will appear in the CDC’s Morbidity and Mortality Weekly Report. Doctors and health officials have often relied on MMWR for official vaccine guidance.

Hughes accused Kennedy of making changes to the charter to circumvent the judge’s ruling and further Kennedy’s push to undermine confidence in vaccines.

“They’re basically creating more room to bring in more questionable people to platform more misinformation,” Hughes said. He declined to say whether the AAP plans to challenge the changes in court, only saying the group is watching them very closely.

Gostin was more critical, saying, “The new charter is a blatant attempt to engineer ACIP into an anti-vaccine tool.”

In an emailed statement, Andrew Nixon, a spokesperson for the Department of Health and Human Services, said the ACIP charter renewal and its publication are routine statutory requirements and “do not signal any broader policy shift.”

“Unless officially announced by HHS, any assertions about next steps are speculation,” Nixon said.

Reiss said she’s skeptical of the idea that Kennedy will name a new ACIP soon, saying HHS would need to show it carefully vetted any new members if it wants the panel to withstand court scrutiny.

She added that the White House is also unlikely to want fresh controversy over vaccines heading into the midterms.

CORRECTION (April 12, 2026, 12:50 p.m. ET): A previous version of this article misquoted Dorit Reiss in one instance. She said “cadre,” not “cattle.”