Dr. Rochelle Walensky, the head of the Centers for Disease Control and Prevention, resigned on Friday despite admitting she had “mixed feelings” about the decision. Walensky, whose public profile shot up during the COVID pandemic, did not give an exact reason for her departure but cited the end of the COVID emergency in her resignation letter to President Joe Biden. The World Health Organization said Friday that COVID no longer qualifies as a global emergency, and U.S. emergency declarations will expire next week. “The end of the COVID-19 public health emergency marks a tremendous transition for our country, for public health, and in my tenure as CDC Director,” she wrote to Biden. “I took on this role, at your request, with the goal of leaving behind the dark days of the pandemic and moving CDC—and public health—forward into a much better and more trusted place.” Walensky served as CDC director for two years; her last day will be June 30.