The head of the Centers for Disease Control and Prevention on Wednesday said the agency must make drastic changes to respond better and faster to public health emergencies, following missteps during the Covid pandemic. The agency has faced widespread criticism throughout the pandemic for its slow responses and often confusing messaging on masking and other mitigation measures. "In our big moment, our performance did not reliably meet expectations," [Dr. Rochelle] Walensky said. Dr. Richard Besser, former acting CDC director and current president of the Robert Wood Johnson Foundation, said overhauling the agency's public messaging is "absolutely essential." "A lot of the scientists at CDC are really good at doing science, and a lot of the responders are really good at doing response," he said. "But that doesn't mean they're good at explaining it in ways that will be useful to the general public." That's potentially a lasting problem for an agency that's often been lagging in its public outreach, said Dr. Mario Ramirez, an emergency physician and former pandemic and emerging threats coordinator under President Barack Obama. "The real challenge that faces CDC," Ramirez said on NBC News Now, "is that it is extremely difficult to communicate complex scientific issues at a speed that is so fast, faster than the Twittersphere." "The margin for error is so small. If you make a mistake in public health, it takes a very long time to regain public trust," he said.