A federal judge issued a stay on key elements of Health and Human Services Secretary Robert F. Kennedy Jr.’s effort to overhaul U.S. childhood vaccine policy, blocking the CDC’s revised immunization schedule and pausing appointments to the Advisory Committee on Immunization Practices. The order, issued by U.S. District Judge Brian Murphy, effectively prevents the reconstituted ACIP from meeting and implementing the new schedule. Medical groups including the American Academy of Pediatrics had challenged the changes; plaintiffs argued the replacements and reduced vaccine recommendations risk public health. HHS indicated it may appeal. The ruling creates immediate operational uncertainty for vaccine advisory processes and underscores risk in abrupt regulatory restructurings.