Size of Creutzfeldt-Jakob disease epidemic associated with cadaveric dura transplantation

BACKGROUND: Ongoing surveillance following the 1996 Japanese nationwide survey on dural-graft-associated Creutzfeldt-Jakob disease (d-CJD) has found that, of all d-CJD cases occurring globally, most patients were identified in Japan. Despite wide recognition that the epidemic is the consequence of shortcomings in the regulation of organ transplantation and the tardy decision-making by the Japanese health ministry, the size of the d-CJD epidemic remains unknown. METHODS: To estimate the overall size of the d-CJD epidemic, a mathematical model was constructed using data on 132 d-CJD patients from the Japanese nationwide surveillance system from 1996 to 2008. RESULTS: Our bayesian model predicted the size of the epidemic to be 163 patients (95% bayesian credible set: 147-183), suggesting that the probability of observing a total of 200 d-CJD patients in the future is low. Further, using a model which included a hypothetical 1987 ban on the use of dura mater, we estimated that the number of patients developing d-CJD would have been between 82 and 122, had Japan acted sooner to counteract the influx of tainted grafts. CONCLUSION: From a public health point of view, minimizing the number of patients exposed should be the highest priority in stemming future epidemics.