Health Secretary Robert F. Kennedy Jr. is rewriting the rules of membership for a key vaccine advisory panel, according to a document published by his department on Monday, after a judge last month declared most of his prior selections unqualified and put their decisions on hold.

The Advisory Committee on Immunization Practices, which advises the Centers for Disease Control and Prevention on the use of vaccines, had been a major tool in Kennedy's efforts to reshape U.S. vaccine policy.

In a March 16 decision, Boston-based U.S. District Judge Brian Murphy concluded that ACIP had been unlawfully reconstituted after Kennedy, a longtime anti-vaccine activist, last year removed and replaced all 17 independent experts who previously served on the panel, adding several members who share his controversial vaccine views.

In his decision, Murphy concluded that Kennedy's ACIP panel violated the Federal Advisory Committee Act and repeatedly pointed to the panel's charter, which required that its members have expertise in the use and research of vaccines and immunization practices.

On Monday, the Department of Health and Human Services led by Kennedy published a renewal of the charter that broadens the list of expertise for individuals who could serve on that panel, which makes recommendations impacting the use of vaccines, including the U.S. childhood immunization schedule.

A previous version of the charter signed by Kennedy in December stipulated that panel members should be knowledgeable about immunization practices and public health, and have expertise using vaccines in clinical practice or preventive medicine or have expertise in vaccine research, or in vaccine efficacy and safety.

Two former ACIP members appointed by previous administrations said the new charter appears to broaden the requirements for membership, listing examples of specialists in biostatistics and toxicology.