Creutzfeldt‐Jakob disease lookback study: 21 years of surveillance for transfusion transmission risk

BACKGROUND Transfusion transmission of human prion diseases has been observed for variant Creutzfeldt‐Jakob disease (vCJD), but not for the classic forms of prion disease (CJD: sporadic, genetic, and iatrogenic). Although the presence of prions or misfolded prion proteins in blood has been documented in some patients with the most common form of CJD, sporadic CJD, no transfusion‐transmitted cases of CJD have been recognized. Since 1995, the American Red Cross has conducted a lookback study of the recipients of blood products from donors who develop CJD to assess the risk of blood‐borne CJD transmission in the United States. STUDY DESIGN AND METHODS Blood donors subsequently diagnosed with confirmed or probable CJD were enrolled and the consignees were asked to identify the recipients of their blood products. These donors' transfusion recipients are traced annually with the National Death Index to see if they subsequently die of CJD. RESULTS To date, 65 CJD donors have been enrolled along with 826 of their blood recipients. These recipients have contributed 3934 person‐years of follow‐up and no transfusion‐transmitted cases of CJD have been recognized. CONCLUSION From this study, as well as other epidemiologic studies, there is no evidence of CJD transfusion transmission; this risk remains theoretical.