Évaluation du risque transfusionnel vis-à-vis de la variante de la maladie de Creutzfeldt-Jakob en France

Abstract

The latest updates (February 2004 and February 2005) of the analysis of the risk of transmission of the agent of Creutzfeldt-Jakob disease (CJD) by blood and blood products in France firstly reported in 2000, were triggered by the two cases of probable transmission of variant CJD (vCJD) by transfusion reported in the UK, and the notification of two French cases of vCJD who had been blood donors on several occasions before clinical onset. Even though some figures of the quantitative assumption used in the risk analysis have been modified since 2000, the conclusion as regards the risk for blood cellular component is considered unchanged: it can be assumed that one unit of labile blood products will contain more than one infectious unit if the donor is incubating the disease. Therefore, the residual risk of receiving by transfusion one infectious blood unit is depending on the prevalence of subjects incubating the disease in the blood donor population. For this particular aspect, the expected number of clinical vCJD cases to occur in France has been lowered since 2000. However, the worst-case scenario of 300 cases in the next 60 years has been maintained in the risk analysis, leading to the hypothesis that one blood donor per 120,000 could be infectious. In conclusion, the risk of getting one infectious blood unit is considered probable to a level of 1/120,000, but the benefit outweighs the risk if the use of transfusion is restricted to well justified indications and if patients are informed a priori and a posteriori.