Although the prevalence of vCJD (a human form of “Mad Cow Disease”) was successfully reduced between 2000 and 2004, the alarming peak in cases led to concern about the disease’s possible transmission via various pathways. Surgical instruments were considered to be a plausible, if surprising potential risk. The work was undertaken for the UK Department of Health and contributed to official reports by the UK government. Models helped simulate potential transmission rates and the impact of mitigation policies on the general population. A wide-ranging review by both medical and modelling experts undertook a very detailed verification and validation exercise on models used in the study. The case is a strong example of model-informed policy in health-care, specifically concerning disease transmission – a topic on which many valuable system dynamics projects have been carried out.