It has been a tumultuous year for federal vaccine policy – and children are starting to feel the effects. Amidst a major measles outbreak, the Centers for Disease Control and Prevention (CDC) chose to roll back nearly half of all childhood vaccination recommendations in early January. As readers of Say Ahhh! Health Policy Blog might recall, this came after CDC’s Advisory Committee on Immunization Practices (ACIP) voted to change long-standing recommendations for a universal birth dose of the Hepatitis B vaccine. ACIP has been in the news since then-recently-appointed Secretary of Health and Human Services (HHS) Robert F. Kennedy Jr. dismissed nearly all ACIP members and reconstituted the committee with new members, including some vocal vaccine skeptics. This combination of the change in ACIP members and recommendations, as well as the CDC’s change in the childhood vaccination schedule, was at the heart of a recent ruling in a lawsuit filed by the American Academy of Pediatrics (AAP) and others.
In the lawsuit, the plaintiffs challenged four key actions: (1) the January 2026 CDC Memo revising the childhood immunization schedule, (2) the May 2025 Directive removing its COVID-19 vaccination recommendation for pregnant women and healthy children, (3) Secretary Kennedy reconstituting ACIP, and (4) three votes taken by the newly reconstituted ACIP (discontinuing the use of thimerosal, in the production of influenza vaccines, changing the COVID-19 vaccine recommendation for adults and children from routine to shared clinical decision making (SCDM), and changing the hepatitis B birth dose from routine to SCDM). The AAP sought a preliminary injunction, essentially asking the judge to press pause on these four actions and to stay the appointments of the new ACIP members—which would effectively prevent the committee from operating—while the case makes its way through the court.
In the ruling issued on March 16, 2026, the court generally agreed with AAP: because the plaintiffs are likely to succeed on the merits of the case and likely to suffer irreparable harm in the absence of preliminary relief, the court stayed the January 2026 CDC Memo, the appointments of the new ACIP members, and all votes taken by the newly reconstituted ACIP. This is a victory, albeit a preliminary one. Here’s a more detailed breakdown of the court order.
1. January 2026 CDC Memo revising the childhood immunization schedule
On January 5, 2026, then acting Director of the CDC Jim O’Neill released a Decision Memorandum (“January 2026 CDC Memo”) dramatically limiting the childhood immunization schedule. The plaintiffs argued that the January 2026 CDC Memo violated the Administrative Procedures Act (APA) because it is arbitrary and capricious. The court found that the January 2026 Memo is reviewable (plaintiffs having met the burdens of standing, final agency action), contrary to law, and arbitrary and capricious. On the “contrary to law” finding, the court emphasized that multiple federal statutes explicitly tie coverage obligations to ACIP’s recommendations—including the Vaccines for Children program and Medicaid/CHIP, as well as the Affordable Care Act’s requirement that insurers cover vaccines “recommended by ACIP” at no cost and similar provisions governing veterans’ benefits. Because Congress specifically named ACIP in these statutes, the court held that the CDC Director could not bypass the committee when revising the immunization schedule. On the arbitrary and capricious finding, the court held that even if bypassing ACIP were not strictly illegal, the government provided no explanation for abandoning the CDC’s decades-long practice of acting only on ACIP’s recommendations. As a result, the court stayed the January 2026 Memo revising the CDC’s childhood immunization schedule. Therefore, the previous schedule is now back in effect. Note that because the court also stayed the 2025 ACIP votes (see Section 4 below), the restored schedule is the June 2024 schedule.
2. May 2025 Directive removing the COVID-19 vaccination recommendation for pregnant women and healthy children
On May 27, 2025, Secretary Kennedy ordered the CDC to stop recommending that pregnant women and healthy children receive the COVID-19 vaccine (the “May 2025 Directive”). The plaintiffs argued that the May 2025 Directive violated the APA because it is arbitrary and capricious. However, the court found that the plaintiffs did not meet the burden of establishing that this challenge is viable on threshold questions of mootness and finality, thus no preliminary relief was ordered. Essentially, if the May 2025 Directive is a final agency action, as AAP argued, it may have been mooted by subsequent agency actions, such as the January 2026 CDC Memo described above. And if the May 2025 Directive was not a final agency action, as the Department argued, it is not reviewable. Importantly, the court explicitly declined to rule on which characterization is correct—it held only that plaintiffs had not met the burden required to justify a preliminary injunction on this specific challenge, and left the question open for the merits phase of the case.
3. Secretary Kennedy reconstituting ACIP
On June 9, 2025, Secretary Kennedy terminated all 17 members of ACIP and replaced them with new members. Secretary Kennedy also terminated the participation of members of liaison organizations on ACIP workgroups. The plaintiffs argued that reconstituting ACIP violated the Federal Advisory Committee Act (FACA) and the APA. The court found that plaintiffs met the burdens of standing (showing injury-in-fact related to the removal of plaintiff organizations from the ACIP workgroups) and contrary to law (finding the newly reconstituted ACIP is not ‘fairly balanced’ as required by FACA), demonstrating a strong likelihood of prevailing on the FACA claim.
On the question of balance, the court was pointed: of the 15 current ACIP members, only 6 appeared to have any meaningful experience in vaccines—the core focus of the committee. At least 6 members appeared to lack any vaccine-related expertise or qualifications whatsoever, and 3 others had only tangential experience. The court noted that ACIP is not simply a committee of doctors or public health experts; it is a body specifically dedicated to vaccine recommendations, and a committee of non-experts cannot be said to represent ‘fairly balanced points of view’ within the relevant scientific community.
The court further found that the appointment process itself was fatally flawed. Historically, ACIP appointments took approximately two years and involved broad outreach to professional organizations, detailed application requirements, letters of recommendation, and an in-depth review by the ACIP Steering Committee. By contrast, Secretary Kennedy appointed the first batch of new members just two days after terminating the prior members, the entire process appeared to take less than four months, and no Federal Register notice was issued as required by standard practice. Because Secretary Kennedy bypassed this process without articulating any reason for doing so, the court found that the plaintiffs also demonstrated a strong likelihood of prevailing on the APA arbitrary and capricious claim. As a result, the court stayed the appointments of the new ACIP members.
4. Votes taken by the newly reconstituted ACIP
As noted above, the newly constituted ACIP voted three times to change vaccine recommendations, and the court stayed all three votes. At the June 2025 meeting, ACIP voted to require flu shot manufacturers to discontinue the use of thimerosal in influenza vaccines for children, pregnant people, and adults. At the September 2025 meeting, ACIP voted to downgrade the COVID-19 vaccine recommendation for adults and children from routine to SCDM. At the December 2025 meeting, ACIP voted to recommend SCDM for parents deciding whether to give the hepatitis B vaccine—including the birth dose—to infants born to women who test negative for the virus. Because the court determined that the committee that took these votes likely violates FACA, it stayed all three votes as well.
It is important to emphasize that this is a preliminary ruling, not a final one. The court has found that plaintiffs are likely to succeed on the merits and are likely to suffer irreparable harm—the legal threshold for a preliminary injunction—but the merits of the case will be fully briefed and decided in subsequent proceedings. The government may also appeal this ruling. For now, however, the June 2024 childhood immunization schedule is back in effect, the newly appointed ACIP members’ appointments are stayed, and all votes taken by the reconstituted committee are paused.
