U.S. health officials at the CDC have been ordered to halt all collaboration with the World Health Organization (WHO), following President Trump's recent executive order for a U.S. withdrawal from the agency. The abrupt directive affects all staff engaged in various capacities with WHO and could significantly impact ongoing investigations into infectious diseases like Marburg virus and mpox. Experts warn that this move undermines global health coordination and heightens risks as the world contends with emerging health threats. The U.S. withdrawal entails a year-long process that requires Congressional approval and financial obligations.