Donor Exclusion to Address Theoretical Risk of Transmission of variant Creutzfeldt-Jakob Disease (vCJD) through the Blood Supply

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Donor Exclusion to Address Theoretical Risk of Transmission of variant Creutzfeldt-Jakob Disease (vCJD) through the Blood Supply (PDF Version, 95 Kb)
Date: 2001-10-22

UNITED KINGDOM, FRANCE & WESTERN EUROPE

1. PURPOSE

The purpose of this Directive is to advise all licenced Canadian blood establishments to take further measures to reduce the theoretical risks of transmission of vCJD through the blood supply. This is to be accomplished by excluding from donating blood, all persons who:

• have spent a cumulative period of time of 3 months or more in the United Kingdom(UK) consisting of England, Scotland, Wales, Northern Ireland, Isle of Man, the Channel Islands between the years 1980 to 1996; or
• have spent a cumulative period of time of 3 months or more in France between the years 1980 to 1996; or
• have spent a cumulative period of time of 5 years or more in countries of Western Europe(WE) consisting of Germany, Italy, Netherlands, Switzerland, Austria, Belgium, Spain, Republic of Ireland, Portugal, Denmark, Luxembourg, Liechtenstein between the years 1980 and ongoing; or
• have received a transfusion of whole blood or blood components in the UK between the years 1980 and ongoing.

The period of time of three months or more spent in the UK or France is not based on a combination of time in either country. The period spent in the above noted WE countries considers either the time spent individually in each country or any combination of time spent in the various countries so that cumulatively, the residence period requiring deferral amounts to 5 years or more .

2. BACKGROUND

Variant Creutzfeldt-Jakob disease (vCJD), first described in 1996, is a "new" disease, linked with the outbreak of Bovine Spongiform Encephalopathy (BSE) in cattle.

While there have been no cases of vCJD attributable to the use of human blood or plasma derivatives to date, lack of experience with this condition and the causative agent, together with limited knowledge available on certain biological effects associated with this infection (e.g. the lack of information on the concentration and infectivity of the vCJD prion in blood), do not allow for conclusion that it can not occur. In addition, a report that BSE in sheep can be transmitted within that species through blood transfusion, suggests that theoretically, vCJD may have the potential to spread through human blood or blood derivatives. Scientific knowledge of the Transmissible Spongiform Encephalopathies (TSEs) has been hampered by the long incubation period of the known TSE infectious agents (e.g. vCJD and BSE) and the lack of diagnostic procedures available for early detection. Consequently, Health Canada (HC) wishes to mitigate the risks of potential human to human transmission of vCJD with policies on blood donor deferral for persons who have spent time in the UK, or France or WE.

In considering this potential risk and measures to deal with it, the principle has been adopted that one must seek to apply measures which will reduce the targeted risk without jeopardizing the safety of the blood system in other ways. Using this rationale, Health Canada issued Directives on August 17, 1999 and August 20, 2000 requiring the exclusion from blood donation of all persons who had spent time amounting cumulatively, to a period of 6 months or more in the UK or France between the years 1980 to 1996, inclusive. Based on recent scientific knowledge available since the issuance of the 1999 and 2000 Directives, Health Canada, in consultation with stakeholders including Canadian Blood Services(CBS) and Héma-Québec(HQ), is directing industry to tighten the blood donor deferral for the UK and France to 3 months or more and to add a deferral based on 5 years or more spent in the above-noted countries of WE.

This new Directive is based on recent scientific knowledge available since the issuance of the 1999 and 2000 Directives and the following new information:

• The total number of cases of vCJD is increasing, with a cumulative total that reached 110 in August, 2001, with 106 in the UK, France reporting 3 cases and one case in the Republic of Ireland;
• The number of observed BSE cases is increasing steadily in West European countries once thought to be free of the disease;
• Brain tissue from BSE-infected primates, injected intravenously into other primates, has been shown to transmit disease;
• Recent research has shown experimental sheep-to-sheep transmission of the BSE agent by blood transfusion.

Recent surveys conducted by CBS and HQ indicate that reducing the deferral period to three months or more for either France or the UK and the addition, of a deferral based on 5 years or more time spent in the above-noted countries of WE, will not jeopardize the blood supply. Health Canada's Population and Public Health Branch has carried out a number of modeling studies to estimate the theoretical risk of acquiring vCJD for those persons who have spent time in the UK. Similar modeling studies have been done to estimate vCJD risk for persons spending time in France and the above noted countries of WE. These risks are not identical and consequently, HC would not require a deferral based on a combination of time in the UK with time spent in France; or a combination of times spent between the above-noted WE countries and either the UK or France. However, WE deferral does allow for a combination of times spent among the above-noted WE countries.

A theoretical risk reduction of 72% is achieved under the 1999 and 2000 Directives. With the implementation of the current Directive, there is expected to be an additional 16-18% reduction of the theoretical risk for an estimated overall risk reduction value of 88-90%. A blood donor loss of around 3% or less is estimated under the current Directive.

3. SCOPE

This Directive applies to all Canadian blood establishments that are licensed to fabricate blood and blood components for transfusion or for further manufacture. Products affected by the Directive include all blood components for transfusion with the exception of: autologous donations, peripheral blood stem cells collected for autologous transplants, rare blood types and products derived from USA-sourced plasma.

4. REGULATORY REQUIREMENTS

Blood establishments are required to submit a Licence Amendment Submission to the Blood and Tissues Division of the Biologics and Genetic Therapies Directorate (BGTD) for review.

An attachment must be included which indicates both the impacts that this measure will have on the donor base and plans to mitigate any such effects. Operators are also encouraged to develop materials to be used in explaining these deferral actions to affected donors in order to foster an appropriate understanding of these precautionary actions.

Regarding the withdrawal of prior donations by deferred donors, Health Canada, will require that all available components collected from these deferred donors, that have not been transfused or pooled for further manufacture, be retrieved.

5. COMPLIANCE DATE

The exclusion is to be introduced as soon as operationally feasible, but not later than three months from the date of this Directive.

6. ADDITIONAL INFORMATION

Blood operators will be required to report semi-annually on the impact of this policy on their donor bases and the supply of blood.

On an ongoing basis, Health Canada may update its guidance in response to new scientific knowledge. If other cases of vCJD are confirmed in a specific country, a risk assessment will be carried out to determine specifically what deferral measures will be required.

The Directive, with a list of supporting references on the Background science, will be posted on an HC website.

Questions concerning the " Donor Exclusion to Address Theoretical Risk of Transmission of variant CJD through the Blood Supply" should be directed to:

Biologics and Genetic Therapies Directorate
Blood and Tissues Division
3rd Floor LCDC Building #6
Postal Locator 0603C
Tunney's Pasture
Ottawa, Ontario
KIA 0L2

7. REFERENCES

Scientific references used in the development of the Directive's "Background" Section:

1. Monthly statistics on the United Kingdom's CJD cases http://www.doh.gov.uk/cjd/stats/aug01.htm
   
   and EUROCJD and NEUROCJD: The European and Allied Countries Collaborative Study Group of CJD(EUROCJD) plus the Extended European Collaborative Study Group of CJD(NEUROCJD) http://www.eurocjd.ed.ac.uk/
2. Monthly statistics on the cases of BSE determined through testing in the European countries. Monthly BSE testing - Cumulative table from January to May 2001 http://europa.eu.int/comm/food/fs
   /bse/testing/bse_test06_en.pdf - BSE testing - May 2001
   
   and Office International des Epizooties - Number of reported cases of BSE worldwide http://www.oie.int/eng/info/en_esbmonde.htm
3. Corinne Ida Lasmézas et al. PNAS, March 27, 2001, vol.98(7),4142-4147 "Adaptation of the bovine spongiform encephalopathy agent to primates and comparison with Creutzfeldt-Jakob disease: Implications for human health" http://www.pnas.org/cgi/doi/10.1073/pnas.041490898
4. Houston F, Foster J.D., Chong A, et al. Transmission of BSE by blood transfusion in sheep. Lancet 2000; 356:999-1000

The modelling studies carried out by Health Canada's Population and Public Health Branch to estimate the theoretical risk of acquiring vCJD under the conditions of the Directive can be found on the Health Canada website with URL: http://www.hc-sc.gc.ca/sab-ccs/sep2000_BSE_vCJD_slide11_e.html