Kennedy Jr.'s installation atop the nation’s health bureaucracy. The Advisory Committee on Immunization Practices (ACIP) normally holds multiple meetings a year, reviews scientific data and makes recommendations to the director of the Centers for Disease Control.

Kennedy, who has called for public health agencies to focus on chronic diseases, was sworn in after a close Senate vote.

Health and Human Services officials said the postponement was to accommodate public comment ahead of the meeting but experts decried the delay.