Attorney General Phil Weiser joins lawsuit challenging HHS Secretary Kennedy’s illegal overhaul of federal childhood immunization policy

Feb. 24, 2026 (DENVER) – Attorney General Phil Weiser today joined a multistate lawsuit challenging the Trump administration’s radical overhaul of the nation’s childhood immunization schedule. The complaint filed today names Health and Human Services Secretary Robert F. Kennedy, Jr., Centers for Disease Control and Prevention Acting Director Jay Bhattacharya, and HHS and the CDC as defendants.

The lawsuit challenges a January 5, 2026, CDC “Decision Memo” that stripped seven childhood vaccines—those protecting against rotavirus, meningococcal disease, hepatitis A, hepatitis B, influenza, COVID-19, and respiratory syncytial virus—of their universally recommended status. The complaint also challenges the unlawful replacement of the Advisory Committee on Immunization Practices (ACIP), the expert federal panel that has guided U.S. vaccine policy for decades.

“Secretary Kennedy and the CDC disregarded federal law, ignored scientific evidence, and put our children in danger by gutting recommended childhood vaccines. Vaccines remain safe and effective, and they are critical for protecting America’s children and public health. Lower vaccination rates will lead to an increase in preventable diseases, which will put stress on our public health system. We’re suing to reverse this dangerous decision and restore a vaccine policy practice that has saved lives,” Attorney General Weiser said.

In June 2025, Secretary Kennedy abruptly fired all 17 ACIP voting members and replaced them with individuals who lack the scientific qualifications required by ACIP’s own charter and the Federal Advisory Committee Act. A majority of ACIP members have expressed views aligned with Secretary Kennedy’s well-documented opposition to vaccines.

In December 2025, the overhauled ACIP reversed nearly 30 years of CDC policy by eliminating the recommendation for a universal hepatitis B birth dose—a vaccine that is up to 90 percent effective in preventing perinatal infection when administered within 24 hours of birth.

Shortly thereafter, the CDC expanded its ideological attack on routine childhood vaccines. On January 5, 2026, then-Acting CDC Director Jim O’Neill—who has no medical or scientific background—signed off on a “Decision Memo” that downgraded seven vaccines from the recommended childhood vaccination schedule to a lesser status that invites confusion and uncertainty.

The Decision Memo was not based on any new scientific evidence, any recommendation by a lawfully constituted ACIP, or any systematic review of the available data. Instead, it relied primarily on superficial comparisons to purported “peer countries”—particularly Denmark—while ignoring the fundamental differences between those nations and the United States, as well as the overwhelming evidence supporting the effectiveness of the CDC’s pre-Kennedy childhood immunization schedule.

Lower vaccination rates will lead to higher rates of infectious disease. For many states, this means a greater strain on their Medicaid programs, more money spent combating misinformation, and wasted resources splitting state laws, regulations, and public guidance from the federal government’s now-untrustworthy recommendations.

Colorado’s statutes and regulations contain several references to ACIP. To address concerns with the ACIP recommendations in regulations, via an emergency rule, the Colorado State Board of Health adopted regulations incorporating the 2025 American Academy of Pediatrics Recommended Child and Adolescent Immunization Schedule.

The plaintiff states are asking the court to declare the Kennedy Schedule and the Kennedy ACIP appointments unlawful, and to enjoin, vacate, and set aside both the new immunization schedule and the unlawful appointments.

Arizona Attorney General Kris Mayes and California Attorney General Rob Bonta are leading the lawsuit and are joined by the attorneys general of Colorado, Connecticut, Delaware, Maine, Maryland, Michigan, Minnesota, New Jersey, New Mexico, Oregon, Rhode Island, Wisconsin, and the Governor of Pennsylvania.

A copy of the lawsuit will be available here after filing.

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Media Contact:
Lawrence Pacheco
Chief Communications Officer
(720) 508-6553 office
lawrence.pacheco@coag.gov