Creutzfeldt-Jakob disease and the risk from blood or blood products.

The occurrence of iatrogenic cases of Creutzfeldt-Jakob disease (CJD) and the isolation of infectivity in some laboratory transmission studies in transmissible spongiform encephalopathies raises the possibility that CJD might be accidentally transmissible through blood or blood products. Epidemiological evidence, although not conclusive, does not suggest that classical CJD is transmitted through this route. However, new variant CJD (nvCJD) might pose greater risks of accidental transmission of infection and mechanisms to reduce the theoretical risk are under consideration. The theoretical risks from CJD and nvCJD must be balanced against the established therapeutic benefits of blood and blood products.