President Donald Trump signed an executive order to withdraw the United States from the World Health Organization, severing ties with global public health efforts. This decision isolates U.S. public health agencies and hampers their ability to coordinate with international counterparts on infectious diseases. Climate change is exacerbating disease spread, with projections indicating that 500 million more people could be exposed to diseases like malaria and dengue fever by midcentury. The withdrawal from WHO could hinder early outbreak warnings and collaborative research efforts, impacting global health security. The Trump administration’s directive to halt external communications at federal health agencies further complicates public health efforts, potentially delaying critical information dissemination.