In the first sentence of “Introduction” on page 400 of the Hematology 2017 American Society of Hematology Education Program, “∼1.9-6.4 per 10,000 children per year and 3.3 per 10,000 adults per year” should read, “∼1.9-6.4 per 100 000 children per year and 3.3 per 100 000 adults per year.” The errors have been corrected in the online version of the article.