A federal judge ruled Monday that Robert F. Kennedy Jr's appointment of new members to a key vaccine advisory committee likely violated federal law, blocking the panel's recent recommendations and postponing an upcoming meeting.

The ruling affects the Advisory Committee on Immunization Practices (ACIP), which provides guidance on routine U.S. immunization recommendations. The judge determined that Kennedy's appointment of what was described as a controversial slate of advisers was conducted improperly under federal procedures.

As a result of the ruling, all votes taken by the committee over the past year have been stayed, meaning they cannot take effect. The judge also invalidated the current membership of the committee, preventing it from meeting as scheduled later this week.

A Department of Health and Human Services official confirmed that the planned meeting has been postponed due to the court's decision. The ruling described the changes to routine immunization recommendations as "arbitrary and capricious."

The Advisory Committee on Immunization Practices typically meets several times per year to review vaccine data and make recommendations that guide immunization policy across the United States. The committee's recommendations are generally adopted by federal health agencies and influence vaccination practices nationwide.