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From: TSS ()
Subject: UK blood donors identified as at increased risk of vCJD are to be notified of their status
Date: July 21, 2005 at 1:32 pm PST

##################### Bovine Spongiform Encephalopathy #####################


UK blood donors identified as at increased risk of vCJD are to be notified of their status

Kate Soldan (kate.soldan@hpa.org.uk)

Emerging Infections and Zoonoses Department, Health Protection Agency Centre for Infections, London, United Kingdom

England’s Department of Health have announced the beginning of notification of a group of individuals who are newly identified as at increased risk of variant Creutzfeldt-Jakob disease (vCJD) in the United Kingdom (UK) [1,2]. These are people who have donated blood that was transfused to patients who subsequently developed vCJD. This currently concerns around 100 donors to three vCJD cases.
vCJD infection has been observed in two recipients of blood transfusions from donors who later developed vCJD [3,4]. One of these recipients did not develop vCJD and died of causes unrelated to the disease. Although other exposures, including, most notably, dietary exposure to BSE, cannot be excluded as the source of these patients’ infections, it is considered highly probable that these two patients were infected by blood transfusion. These reports added to previous evidence of vCJD infectivity in blood obtained from experiments in animals, and led to the conclusion that transfusion should be considered a possible route of vCJD transmission in humans.

Over 2 million blood donations are collected each year in the UK by the blood services, and over half a million patients receive transfusions annually. Of the 150 people who have died from vCJD in the UK to 1 July 2005 [5], only four have been confirmed as having received blood transfusions that may be associated with their subsequent development of vCJD. (For two other cases, symptoms developed before or very shortly after transfusion and therefore transfusion is not considered a possible source of their infections.) For one of these cases, the probable source of infection has already been identified, as one of the donors went on to develop vCJD. For the remaining three cases, transfusion remains a possible source of the recipient’s infection.

A risk assessment by the Department of Health looked at the probability of donors to vCJD cases being the source of a recipient’s infection, and therefore the probability that the donors themselves are infected [6]. The United Kingdom CJD Incidents Panel [7] considered this risk assessment and recommended that such donors should be considered as ‘potentially at-risk of vCJD for public health purposes’ unless the probability of being infected with vCJD (as implied by donation to a vCJD case, and estimated with precautionary, or ‘worst case’, assumptions) falls clearly below 1%.

Unless there is evidence to the contrary, the assumptions for this calculation are: that an infected donation would certainly infect the recipient (the ‘worst case’ assumption); that there is no way of distinguishing between the contributing donors (and recipient) in terms of risk of primary vCJD infection (e.g., that all had been resident in the UK during the BSE outbreak), and that there is no other significant alternative infection route for the recipient, such as having been operated on with instruments previously used for healthcare interventions on a patient with vCJD.

These individuals are being informed that they are 'potentially at-risk of vCJD for public health purposes' so that special public health precautions can be taken to reduce the risk of person-to-person transmission of vCJD during their healthcare. Specifically these are: not to donate blood, organs or other tissues, and to inform their healthcare providers of their 'at-risk' status in order that infection control guidance [8] can be implemented for the instruments used in certain invasive healthcare procedures (and so that certain invasive healthcare procedures that have already been carried out on them can be considered by the CJD Incidents Panel).

The 100 or so individuals involved are being informed by the UK Blood Services. Their general medical practitioners are being briefed by the Health Protection Agency and Health Protection Scotland so that they can provide further information and support to their patients, and assist with implementation of the recommended public health precautions, as required. Where past invasive healthcare procedures have been conducted on these individuals, and potentially contaminated instruments may be a risk for other patients, local health protection staff are asked to consult the CJD Incidents Panel for advice about whether any actions should be taken.

Since its establishment in 2000, the CJD Incidents Panel has issued advice relating to several groups of patients identified as at increased risk of CJD. Other groups of patients who are considered to be ‘potentially at-risk of vCJD for public health purposes’ include: certain patients who have been operated on with instruments previously used for healthcare interventions on a patient with vCJD; recipients of blood from donors who later developed vCJD, and patients who have been treated with plasma products that may have been contaminated with vCJD infection. This new notification of ‘donors to vCJD cases’ is a further precautionary measure to reduce the possible risk of secondary transmission of vCJD in the UK. Further information about this notification can be found at http://www.hpa.org.uk/infections/topics_az/CJD/vCJDBloodDonors.htm.

This article has been adapted by the author from reference 1


References:
1.. HPA. New group of individuals notified of increased risk of vCJD. CDR Weekly 2005; 15(29): news. (http://www.hpa.org.uk/cdr/index.html)
2.. Notification exercise begins to reduce risk of vCJD transmission. Department of Health, press release 2005/0256, 20 July 2005. (http://www.dh.gov.uk/PublicationsAndStatistics/PressReleases/PressReleasesNotices/fs/en?CONTENT_ID=4116206&chk=4YsTe9)
3.. Llewelyn CA, Hewitt PE, Knight RSG, Amar K, Cousens S, Mackenzie J, et al. Possible transmission of variant CJD disease by blood transfusion. Lancet 2004; 363;417-421.
4.. Peden AH, Head MW, Ritchie DL, Bell JE, Ironside JW. Preclinical vCJD after blood transfusion in a PRNP codon 129 heterozygous patient. Lancet 2004; 364;527-529.
5.. CJD Statistics. Numbers of deaths of definite and probable vCJD cases in the UK, reported to the CJD surveillance unit in Edinburgh up to 1st July 2005. The National Creutzfeldt-Jakob Disease Surveillance Unit website, updated 4 July 2005. (http://www.cjd.ed.ac.uk/figures.htm)
6.. Standards and Quality Analytical Team (Economics, Statistics and Operational Research), Department of Health. Assessing the Implications for Blood Donors if Recipients are infected with vCJD. London; Department of Health; 2004, with new preface July 2005. (http://www.dh.gov.uk/assetRoot/04/11/53/12/04115312.pdf)
7.. The CJD Incidents Panel [http://www.hpa.org.uk/infections/topics_az/cjd/incidents_panel.htm] is an expert committee established on behalf of the UK Chief Medical Officers in 2000.
8.. Transmissible spongiform encephalopathy agents: safe working and the prevention of infection. Guidance from the Advisory Committee on Dangerous Pathogens and the Spongiform Encephalopathy Advisory Committee. Department of Health website, June 2003, updated 20 July 2005. (http://www.advisorybodies.doh.gov.uk/acdp/tseguidance/index.htm)

http://www.eurosurveillance.org/ew/2005/050721.asp#5

TSS

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