Written question asked by Jason McCartney (Conservative) on Monday, 9 May 2011, in the House of Commons. It was due for an answer on Wednesday, 11 May 2011. It was answered by Anne Milton (Conservative) on Monday, 16 May 2011 on behalf of the Department of Health.

Creutzfeldt-Jakob Disease

Question: To ask the Secretary of State for Health (1) what estimate he has made of the number of people who are considered to be at risk of contracting variant Creuztfeldt-Jakob disease;

Answer: A study published in 2004 of stored appendix and tonsil tissue samples found abnormal prion protein in three appendices out of 12,674 samples. This suggested a population prevalence of about one in 4,000, though with very wide confidence interval of between one in 1,400 and one in 20,000. A further study of over 96,000 tonsils pairs is nearing completion, and a study of 30,000 appendix samples is due to be completed in 2012. Prevalence estimates are kept under active review by the relevant expert scientific advisory committees, who will review all the evidence on the completion of these ongoing studies.In England about 4.4% of the population are blood donors, and the prevalence of potentially infective blood donors remains unknown. Not all of the individuals in the 2004 published study would be of an age eligible to donate blood, nor is it clear whether presence of abnormal prion protein in tissues such as the appendix or tonsils indicates that the blood of such a donor would transmit variant Creutzfeldt-Jakob disease. All precautionary measures are assessed in the context of the fundamental uncertainties about prevalence.

Secondary information