title: Ten-year follow-up of two cohorts with an increased risk of variant CJD: donors to individuals who later developed variant CJD and other recipients of these at-risk donors.
abstract: BACKGROUND
  Transmission of variant Creutzfeldt-Jakob disease (vCJD) through blood transfusion is implicated in three deaths and one asymptomatic infection. Based on this evidence, individuals assessed to be at increased risk of vCJD through donating blood transfused to individuals who later developed vCJD, or through being other recipients of such donors, are followed up to further understand the risks of vCJD transmission through blood.
  
  
  OBJECTIVE
  To provide a ten-year follow-up of these at-risk cohorts.
  
  
  METHODS
  Blood donors to patients who later died from vCJD were identified by the Transfusion Medicine Epidemiological Review (TMER) study. A reverse risk probability assessment quantified the risk of blood transfusion or exposure through diet as the source of vCJD in the recipients. Donors to these recipients, and these donors' other recipients, with a probability risk above 1%, are classified as at increased risk of vCJD for public health purposes. These cohorts are monitored for any vCJD occurrences.
  
  
  RESULTS
  A total of 112 donors and 33 other recipients of their donated blood have been classified as at increased risk. After 2397 and 492 vCJD-free years of follow-up, respectively, no deaths in either at-risk cohort were of vCJD-related causes.
  
  
  CONCLUSIONS
  The at-risk cohorts have survived disease-free far longer than the estimated incubation time for dietary-acquired vCJD (donors) and transfusion-acquired disease (other recipients). However, due to our still limited understanding of, and a lack of a reliable test for, asymptomatic vCJD infection, public health follow-up is necessary for continued monitoring of at-risk cohorts.
authors.affiliation: Centre for Infectious Disease Surveillance and Control, National Infection Service, Public Health England, London, UK.
authors.forename: M
authors.initials: M
authors.lastname: Checchi
authors.affiliation: Transfusion Microbiology, National Health Service Blood and Transplant, London, UK.
authors.forename: P E
authors.initials: PE
authors.lastname: Hewitt
authors.affiliation: Department of Health, Public and International Health Directorate, London, UK.
authors.forename: P
authors.initials: P
authors.lastname: Bennett
authors.affiliation: Health Protection Scotland, NHS National Services Scotland, Edinburgh, UK.
authors.forename: H J T
authors.initials: HJ
authors.lastname: Ward
authors.affiliation: National CJD Research & Surveillance Unit, University of Edinburgh, Western General Hospital, Edinburgh, UK.
authors.forename: R G
authors.initials: RG
authors.lastname: Will
authors.affiliation: National CJD Research & Surveillance Unit, University of Edinburgh, Western General Hospital, Edinburgh, UK.
authors.forename: J M
authors.initials: JM
authors.lastname: Mackenzie
authors.affiliation: Centre for Infectious Disease Surveillance and Control, National Infection Service, Public Health England, London, UK.
authors.forename: K
authors.initials: K
authors.lastname: Sinka
mesh_terms: D000328:Adult; D058070:Asymptomatic Diseases / Q000453:epidemiology; D001782:Blood Donors; D058731:Blood Safety; D007562:Creutzfeldt-Jakob Syndrome / Q000097:blood / Q000453:epidemiology / Q000635:transmission*; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D018570:Risk Assessment; D065227:Transfusion Reaction
keywords: blood safety; epidemiology; prions; transfusion - transmissible infections