A U.S. district judge issued a temporary block on major elements of Health Secretary Robert F. Kennedy Jr.'s overhaul of federal childhood vaccine policy, staying the CDC's decision to reduce routinely recommended vaccines and pausing appointments to the Advisory Committee on Immunization Practices. The order followed legal challenges from medical societies including the American Academy of Pediatrics and cited likely violations of federal advisory committee rules. The court action leaves existing CDC vaccine schedules intact while the litigation proceeds and raises immediate operational questions about ACIP meetings and vaccine guidance. HHS signaled it will seek reversal of the ruling. Public-health groups called the decision a necessary check on sweeping regulatory changes that, they argue, risk undermining established immunization programs.