Lessons from the response to the threat of transfusion-transmitted vCJD in Ireland.

By the time vCJD was first described in 1996, it was already far too late to offset further disaster from transmission of the disease by blood transfusion: almost all the humans who would be infected and infectious were already diseased. Nothing done by the blood transfusion services around that time, with the exception of excluding transfusion recipients as blood donors, would have made any useful contribution to containing the extent of the epidemic. The ability to spread emerging diseases before the problem is manifest or understood is a fixed and unavoidable feature of blood transfusion as it is practiced today. A second fixed property of blood transfusion is that the root cause of disaster is not within the control of the blood transfusion universe. Strategies that have emerged to cope with similar threat in other enterprises that also contain these properties comprise the components of robust design: surveillance, preparedness for action, engagement, herding together, evasion or avoidance, early adoption of potentially useful measures, engineered resilience, defence in depth, damage limitation including modularity and removal of feedback loops, and contingency, redundancy and failure management, and ultimately, individual escape. Early adoption of leucodepletion based on the possibility that it might work rather than any hard evidence was a good example of threat management. Exclusion of previously transfused donors is a robust mechanism for containing any future infection; optimal blood use structures that provide a national transfusion rate as low as possible also constitute an effective threat management strategy.