Claim: In August 2025, the U.S. Centers for Disease Control and Prevention's (CDC) immunization chief, Dr. Demetre C. Daskalakis, posted a resignation letter denouncing Health and Human Services (HHS) Secretary Robert F. Kennedy Jr.'s leadership of HHS and the CDC. Daskalakis was, in fact, the CDC's director of the National Center for Immunization and Respiratory Diseases before he resigned on Aug. 28, 2025. He also posted his full, 1,200-word resignation letter on his X account and on his verified Instagram, indicating the letter's authenticity. At a hearing, Secretary Kennedy said that Americans should not take medical advice from him. Daskalakis' full letter can be found here.