WASHINGTON, Dec 17 (Reuters) - The U.S. Department of Health and Human Services has canceled millions of dollars in grants awarded to the American Academy of Pediatrics, it said on Wednesday, including ones the group said were aimed at reducing sudden infant death and early detection of autism. The move comes as the AAP, a vocal critic of HHS Secretary Robert F. Kennedy Jr., challenged vaccine policies enacted under his leadership in federal court. Kennedy, a longtime critic of vaccines, has accused the organization of accepting funding from drug and vaccine makers to further their interests. These grants, previously awarded...