Batches of the infected growth hormone were stored in a Department of Health archive as a dried powder. Those who were given the infected growth hormone were all notified many years ago that they were at risk of developing CJD. The people described in the study had all been treated as children with a type of human growth hormone taken from dead donors (cadaver-derived human growth hormone or c-hGH). After that, c-hGH was replaced with a synthetic growth hormone that did not carry the risk of transmitting CJD. Growth hormone donated by humans was prepared in different ways.