Title: Expert judgement and re-elicitation for prion disease risk uncertainties

Authors: Michael G. Tyshenko; Susie ElSaadany; Tamer Oraby; Shalu Darshan; Angela Catford; Willy Aspinall; Roger Cooke; Daniel Krewski

Addresses: McLaughlin Centre for Population Health Risk Assessment, Institute of Population Health, University of Ottawa, 1 Stewart St., Ottawa, Ontario, K1N 6N5, Canada. ' Blood Safety Surveillance and Healthcare Acquired Infections Division, Centre for Infectious Disease Prevention and Control, Public Health Agency of Canada, Ottawa, Ontario, K1A 0L2, Canada. ' McLaughlin Centre for Population Health Risk Assessment, Institute of Population Health, University of Ottawa, 1 Stewart St., Ottawa, Ontario, K1N 6N5, Canada. ' McLaughlin Centre for Population Health Risk Assessment, Institute of Population Health, University of Ottawa, 1 Stewart St., Ottawa, Ontario, K1N 6N5, Canada. ' Blood Safety Surveillance and Healthcare Acquired Infections Division, Centre for Infectious Disease Prevention and Control, Public Health Agency of Canada, Ottawa, Ontario, K1A 0L2, Canada. ' Aspinall and Associates, Cleveland House, High Street, Tisbury SP3 6HF, UK; Bristol University, Queen's Road, Bristol BS8 1RJ, UK. ' Delft University of Technology, Postbus 5, 2600 AA Delft, The Netherlands. ' McLaughlin Centre for Population Health Risk Assessment, Institute of Population Health, University of Ottawa, 1 Stewart St., Ottawa, Ontario, K1N 6N5, Canada; Department of Epidemiology and Community Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, K1H 8M5, Canada

Abstract: Much uncertainty surrounds transmission of transmissible spongiform encephalopathies (TSEs) through blood and blood derived products. A first expert elicitation with 14 experts was conducted in March 2008, and a second re-elicitation involving 11 experts was held a year later in March 2009. Both expert groups were calibrated using a series of seed questions for which values are known, and then were asked to provide their individual judgements on a set of seven target questions for which values are not known or have not been determined through conventional research. Questions dealing with uncertainty of TSE prevalence, genotype effects, susceptibility, and infectivity were answered by the experts. Elicitation can be used to obtain quantitative values for parameters affecting prion uncertainty gaps. We show that the method is amenable to re-elicitation over time allowing refinement of expert opinion as new knowledge becomes available for improved risk assessments where data gaps continue to exist.

Keywords: expert elicitation; bovine spongiform encephalopathy; BSE; variant CJD; Creutzfeldt-Jakob disease; blood safety; risk assessment; iatrogenic transmission; prion disease; risk uncertainties; experts; transmissible spongiform encephalopathies; TSEs; uncertainty; TSE prevalence; genotype effects; susceptibility; infectivity.

DOI: 10.1504/IJRAM.2012.047552

International Journal of Risk Assessment and Management, 2012 Vol.16 No.1/2/3, pp.48 - 77

Published online: 26 Jun 2012 *

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