Estimating the size of the outbreak of new‐variant CJD

Despite the small numbers of New‐Variant Creutzfeldt‐Jakob Disease (vCJD) observed, sufficient human data have now accrued to allow statistical estimation of all three of the important parameters: the mean period between infection and death (the “mortality period”), its variance and the size of the outbreak. The mean mortality period is estimated to lie in the range six to 16 years, with low variances associated with the lower values of mean mortality period (< ten years) that are indicated as most likely. If BSE is indeed the cause of vCJD, then the number of human victims of vCJD is predicted not to exceed a few hundred, and is most likely to be a hundred or less. The study suggests that, while there may be a continuing, small number of deaths from vCJD for some years to come, exposure to the disease from BSE in the UK has more or less ceased at the time of writing.