The Scientific Steering Committee has recently advised the Commission(1) that there is no conclusive scientific evidence for the transmission of variant Cruntzfeld-Jacob disease (vCJD) by blood. However, the Commission is well aware that a theoretical potential for such transmission does exist, and the relevant Scientific Committees continuously monitor scientific evidence on the subject as it arises.

Based on the Committee's findings, the Commission will propose preventive measures as necessary, taking into account also that the Scientific Committee on Medicinal Products and Medical Devices (SCMPMD)(2) recommends a careful consideration of whether the exclusion of donors who stayed for a defined period of time in areas with increased risk of exposure to the bovine spongiform encephalopathy (BSE) agent would provide an increase in safety balanced against its negative impact on supply and donor population.

According to the SCMPMD, the adverse effects of any exclusion criterion on the donor population is not only the possibility of a shortage in supply. Excluded donors have to be replaced by new donors, most probably by first time donors. This replacement creates an additional risk as the prevalence of blood borne infectious diseases in first time donors is significantly higher than in repetitive donors. Any new exclusion measure, therefore, has to be balanced against the calculable risk of human immunodeficiency virus (HIV), hepatitis B virus (HBV) and hepatitis C virus (HCV) transmissions in donations from first time donors.

(1) Opinion of the Scientific Steering Committee of 26/27 October 2000 on the Houston et al paper in the Lancet of 16 September 2000 on the transmission of BSE by blood transfusion in sheep. (2) Update of the Opinion given by the Scientific Committee on Medicinal Products and Medical Devices on The Risk Quantification For CJD Transmission Via Substances of Human Origin of 16 February 2000.