by 2008 offit had become a leading advocate of childhood immunizations. he was opposed by vaccine critics, many of whom believe vaccines cause autism, a belief that has been rejected by major medical journals and professional societies. he received a death threat and received protection by an armed guard during meetings at the cdc. his 2008 book "autism's false prophets" catalyzed a backlash against the antivaccine movement in the u.s. he donated the royalties from the book to the center for autism research at children's hospital of philadelphia. offit serves on the board of the american council on science and health. in 2015, dr. offit appeared in a vaccine awareness video created by robert till in which he advocated for teenage vaccinations.