A coalition of 14 state attorneys general and Pennsylvania’s governor jointly filed a federal lawsuit on Tuesday challenging the Trump administration’s overhaul of the federal childhood immunization schedule.

The complaint, filed in the US District Court for the Northern District of California, names Health and Human Services (HHS) Secretary Robert F. Kennedy Jr and acting Centers for Disease Control and Prevention (CDC) director Jayanta Bhattacharya as defendants. The lawsuit focuses on a January “Decision Memo” signed by then-acting CDC director Jim O’Neill, which demoted seven vaccines, including influenza and COVID-19, from “universally recommended” status to a “shared clinical decision-making” category. HHS defended the decision as the product of a comprehensive scientific review comparing US childhood immunization practices with those of peer-developed nations, with officials emphasizing that all vaccines on the previous schedule would remain fully covered by insurance and existing federal programs.

Tuesday’s complaint uses three legal theories under the Administrative Procedure Act. First, the complaint argues that the Decision Memo was arbitrary and capricious because it bypassed the Advisory Committee on Immunization Practices (ACIP), ignored scientific evidence, and offered no reasoned explanation for departure from a longstanding policy.

Second, the complaint argues the Decision Memo was contrary to law because multiple federal statutes, including the Affordable Care Act, the Medicaid Act and the Vaccines for Children program assign ACIP, not the CDC, as the authority for establishing vaccine schedules.

Lastly, the complaint challenges Secretary Kennedy’s June dismissal of all 17 ACIP voting members and his subsequent appointments, arguing both violated the Federal Advisory Committee Act‘s requirements that committees be “fairly balanced” and free from undue influence by the appointing authority.

In a statement released Tuesday, California Attorney General Rob Bonta elaborated on the lawsuit:

The Trump Administration’s attacks on science are irresponsible and dangerous. Undermining confidence in vaccines will lead to lower vaccination rates and more infectious diseases. It will also drive up costs for states, including increased Medicaid spending and new expenses to combat misinformation and revise public health guidance.

The states allege harms resulting from the vaccine schedule changes, including administrative costs associated with updating state statutes and regulations that cross-reference ACIP recommendations, projected increases in Medicaid expenditures resulting from treatment of diseases that could have been prevented with vaccines, and the use of state public health resources to counter “misinformation.” The states seek declaratory and injunctive relief, asking the court to vacate both the new immunization schedule and the Kennedy ACIP appointments.

This comes amidst ongoing litigation and contention surrounding domestic vaccine programs. Last September, Florida announced a plan to eliminate all vaccine mandates. A current federal lawsuit filed by several medical organizations challenges recent changes to COVID-19 vaccine recommendations for pregnant women and healthy children.