Beyond blood safety.

World Blood Donor Day takes place on 14 June each year. Established in 2005 by the World Health Assembly, it aims to raise global awareness of the need for safe blood and blood products for transfusion and of the critical contribution made by voluntary unpaid blood donors to national health systems.1 The focus for World Blood Donor Day 2010 will be on young donors – our “New Blood for the World”. 14 June happens to be the birthday of Karl Landsteiner, whose observation in 1900 that sera of some individuals agglutinated the red cells of others led to the identifi cation of the blood groups A, B and C (later renamed group O). The discovery of the ABO and other blood group systems enabled blood to be safely transfused without fatal haemolytic transfusion reactions caused by the infusion of incompatible blood. Thus began the fi rst steps towards transfusion safety. Fears of disease transmission have dominated transfusion safety worldwide. The fi rst description of post-transfusion hepatitis by Beeson in 1943 was followed by decades of exhaustive efforts by blood banks and transfusion physicians to make blood as safe as practically possible. The outbreak of AIDS in the 1980s accentuated public demand for a zero-risk blood supply and this, combined with political pressure and liability concerns, would lead to blood safety decisions based on avoidance of all possible risks and religious adherence to the precautionary principle. The blood supply today is protected by multiple layers of safety from donor selection to blood testing. Increasingly sensitive serological and nucleic acid tests for HIV, HBV and HCV have been introduced, enabling a dramatic reduction in the transmission of these viruses through blood transfusion. Transfusion-associated sepsis from bacterial contamination of blood products remains the main infective risk associated with blood transfusion in developed countries, but has decreased in frequency following the implementation of bacteriological testing of platelets. The greatest infectious threat today comes from emerging agents of zoonotic origin, such as human variant Creutzfeldt-Jakob disease, dengue viruses and Babesia,2 and the threat of a completely new pathogen – the “next new virus”. Pathogen reduction (PR) systems should add another layer of safety, by complementing existing tests and reducing the