Introduction
The Advisory Committee on Immunization Practices (ACIP) is the CDC’s principal advisory body on vaccines, shaping the national immunization schedule. In 2025–2026, ACIP underwent a sweeping reconstitution under Secretary Robert F. Kennedy Jr., with 15 new members appointed after June 2025. This reshaping of the committee coincided with a major legal challenge brought by the American Academy of Pediatrics (AAP), culminating in the landmark case AAP v. Kennedy (2026).
The litigation questioned whether the reconstituted ACIP complied with the Federal Advisory Committee Act (FACA), particularly its requirement that advisory committees be “fairly balanced.” The court’s interim order of March 16, 2026, has stayed Kennedy’s vaccine policy decisions and placed ACIP in a state of dormancy.
ACIP Membership Transition
The archived roster from June 2025 listed only 10 members, reflecting a transitional period when several terms had expired. By April 2026, the committee expanded to 15 voting members, all appointed after June 2025, with terms running through June 2029.
Key changes included the appointment of Kirk Milhoan, MD, PhD as Chair in December 2025, alongside new members such as Angelina Farella, Kimberly Biss, Hillary Blackburn, Adam Urato, Raymond Pollak, and Catherine Stein. Established figures like H. Cody Meissner and James Pagano continued their terms, while prominent additions such as Paul Offit, Kevin Ault, Sarah Long, Grace Lee, and Jason Newland brought further expertise.
ACIP Voting Members (Archive vs Current, April 2026)
| Member | Archive (Jun 2025–Mar 2026) | Current (Apr 2026) | Year Appointed | Term Expiry | Change |
|---|---|---|---|---|---|
| Kirk Milhoan, MD, PhD (Chair) | Not listed | Present | Dec 2025 | Jun 2029 | New Chair |
| Mina Zadeh, PhD, MPH (Exec. Sec.) | Present | Present | Ongoing | N/A | No change |
| Angelina Farella, MD | Not listed | Present | Dec 2025 | Jun 2029 | Added |
| H. Cody Meissner, MD | Present | Present | Jun 2025 | Jun 2029 | Continues |
| James V. Pagano, MD, FACEP | Present | Present | Jun 2025 | Jun 2029 | Continues |
| Raymond Pollak, MD, FACS, FRCS | Not listed | Present | Sep 2025 | Jun 2029 | Added |
| Catherine M. Stein, PhD | Not listed | Present | Sep 2025 | Jun 2029 | Added |
| Adam Urato, MD | Not listed | Present | Dec 2025 | Jun 2029 | Added |
| Kimberly Biss, MD | Not listed | Present | Dec 2025 | Jun 2029 | Added |
| Hillary Blackburn, PharmD, MBA | Not listed | Present | Dec 2025 | Jun 2029 | Added |
| Paul Offit, MD | Not listed | Present | 2025 | Jun 2029 | Added |
| Kevin Ault, MD | Not listed | Present | 2025 | Jun 2029 | Added |
| Sarah Long, MD | Not listed | Present | 2025 | Jun 2029 | Added |
| Grace Lee, MD, MPH | Not listed | Present | 2025 | Jun 2029 | Added |
| Jason M. Newland, MD, MEd | Not listed | Present | 2025 | Jun 2029 | Added |
American Academy Of Pediatrics (AAP) v. Kennedy (2026)
The court gave an interim order on 16-03-2026 and the following are the core observations of the court in this case:
(1) The balance of equities and public interest factors weigh in favor of preliminary relief of Stay in favour of AAP, but not Preliminary Injunction.
(2) In drafting equitable relief, courts must consider ‘what is necessary, what is fair, and what is workable.
(3) January 2026 Memo: The parties largely agree that, should the Court issue relief as to the January 2026 Memo, a Stay is appropriate. In the face of the parties’ agreement, the Court finds that a Stay of the January 2026 Memo is an appropriate remedy. To the extent Plaintiffs seek further relief, the Court declines to grant it at this time.
(4) ACIP: Plaintiffs are likely to succeed in showing that the reconstituted ACIP does not comport with FACA’s “fairly balanced” requirement. The Court made this determination not on a mathematical formula but based on the unexplained departure from the MBP and the overall composition of the new committee. These findings go beyond “specific appointments,” and instead suggest that the appointment process, in general, and thus the full committee, was tainted. Thus, the remedy should cover the entire challenged committee.
(5) However, it would be inappropriate for the Court either to enjoin ACIP from meeting, as Plaintiffs suggest, or to effectively select-by-veto a different ACIP, as Defendants suggest. There are many “different balances that can be struck in a committee’s membership.”
(6) It is an agency’s job and prerogative to strike that balance, just as it is this Court’s to say when the agency has failed to do so. Identifying specific members of ACIP who should not have been appointed, based on an incomplete record, or assuming that HHS is wholly incapable of assembling a lawful ACIP at this stage and enjoining it from doing so, would impose a far greater intrusion into Defendants’ operation than merely staying the current appointments.
(7) A stay will prevent the irreparable injury Plaintiffs have shown is likely: while the appointments of the challenged members of ACIP are stayed, ACIP as currently constituted cannot meet, for how can a committee meet without nearly the entirety of its membership?
(8) Moreover, a Stay is “less drastic” than, and thus preferable to, an Injunction. Thus, the Court concludes that the appropriate remedy at this juncture is to Stay the appointments of the thirteen members of ACIP at issue in this motion.
(9) The Court will also stay all votes taken by the challenged ACIP, as they were taken by a committee that this Court has determined likely violates FACA. Though courts have recognized that injunctive relief may be appropriate to remedy a FACA violation, preventing the agency from relying on an advisory committee’s recommendations or work product is the only way to achieve FACA’s purpose of enhancing public accountability. In this instance, ACIP’s votes have actual legal weight that can be mitigated directly by a Stay. Therefore, the Court need not resort to an Injunction.
Conclusion: For the foregoing reasons, Plaintiffs’ motion for preliminary relief is GRANTED IN PART.
(i) The Court STAYS the January 2026 Memo revising the CDC’s childhood immunization schedule pursuant to 5 U.S.C. § 705.
(ii) The Court STAYS the appointments of the thirteen ACIP members appointed on June 11, 2025, September 11, 2025, and January 13, 2026.
(iii) The Court further STAYS all votes taken by the now-stayed ACIP.
Conclusion
The interim order in AAP v. Kennedy reframes the ACIP controversy as a fundamental test of administrative law. The court’s decision to stay both the January 2026 memorandum and the appointments of thirteen ACIP members underscores the judiciary’s role in ensuring that advisory committees remain credible, balanced, and compliant with statutory requirements.
By rejecting both extremes—an injunction that would shut ACIP down entirely and a veto that would allow the court to handpick members—the ruling preserves the agency’s prerogative while enforcing accountability. This balance reflects the principle that advisory committees must serve the public interest, not political expediency.
For now, the pre-June 2025 immunization schedule remains the federal standard, and ACIP is effectively dormant. The litigation’s outcome will determine whether Kennedy’s reconstituted committee can survive judicial scrutiny or whether a new, lawfully balanced ACIP must be assembled.
Ultimately, this case is not only about vaccines but about the integrity of federal advisory committees. It sets a precedent for how courts may intervene when executive actions threaten statutory safeguards, shaping the future of public health governance and the limits of administrative power.