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Variant Creutzfeldt-Jakob disease deferral in Canada: impact of stop dates
Sheila F O'brien1,2, Wenli Fan1, Qi-Long Yi1,2
1Canadian Blood Services, University of Ottawa, Ottawa, ON, Canada.
Insights
Variant Creutzfeldt-Jakob disease (vCJD) travel deferrals in Canada reduce donor loss, with rare non-compliance. "Stop dates" decreased UK/France deferrals, but Western Europe impacts are still emerging.
Area of Science:
- Public Health
- Epidemiology
- Blood Transfusion Safety
Background:
- Variant Creutzfeldt-Jakob disease (vCJD) poses a risk of transmission through blood transfusions.
- Canada defers donors with travel history to the UK, Western Europe, and Saudi Arabia to mitigate this risk.
- Implementation of "stop dates" for travel history aimed to refine deferral criteria and assess donor compliance.
Purpose of the Study:
- To evaluate the long-term impact of vCJD travel deferral policies and "stop dates" on blood donor rates.
- To assess the consistency of donor responses regarding travel history and compliance with deferral rules.
Main Methods:
- Monthly deferral rates were analyzed from 2003-2015 using time series methods (ARIMA).
- Telephone surveys assessed travel history among first-time, repeat deferred, and control donors.
- Anonymous mail surveys evaluated donor compliance with deferral policies.
Main Results:
- Implementation of "stop dates" for UK/France travel significantly reduced deferral rates for both first-time and repeat donors.
- Inclusion of Saudi Arabia in deferrals led to an increase in deferral rates.
- Post-"stop date" analysis showed unchanged deferral rates for first-time Western Europe donors but a decrease in repeat donors.
- Surveys indicated high donor confirmation of deferrable travel (94%) and low non-compliance (0.3% for UK/France deferral).
Conclusions:
- vCJD travel deferrals continue to affect donor numbers, especially first-time donors, but are generally applied correctly with rare non-compliance.
- "Stop dates" effectively reduced deferrals related to UK/France travel.
- The full impact of the Western Europe "stop date" on deferral rates may require longer-term observation.
Background:
To reduce the risk of variant Creutzfeldt-Jakob disease (vCJD) transmission via blood transfusion in Canada, potential donors who spent a cumulative time in the United Kingdom, Western Europe or Saudi Arabia are deferred. "Stop dates" for accumulated time were later implemented for 3 months spent in the United Kingdom or France (1980-1996) and for 5 years elsewhere in Western Europe (1980-2007); Saudi Arabia deferral was implemented with the "stop date" (1980-1996). We evaluated the long-term impact of these deferrals and "stop dates", as well as the consistency of donors' answers to post-implementation screening questions.
Materials And Methods:
The monthly deferral rate was monitored from 2003-2015. Time series methods (ARIMA) were used with interruption when "stop dates" were implemented. A telephone survey of 1,000 donors (250 first-time, 500 repeat deferred donors, 250 non-deferred control donors) assessed travel history (response rate 62%). An anonymous mail survey of 40,000 donors assessed compliance with deferral (response rate 45.3%).
Results:
When the "stop date" for UK/France travel was implemented, the deferral rate decreased for first-time (2.1% to 1.1%, p<0.0001) and repeat (0.2% to 0.03%, p<0.0001) donors. The deferral rate increased after Saudi Arabia was included (mean increase of 0.4% first-time, 0.02% repeat, p<0.0001). After the Western Europe "stop date" the deferral rate was unchanged in first-time donors (1.0% to 1.1%, p=0.5) but decreased in repeat donors (0.03% to 0.02%, p<0.002). In the telephone survey, 94% of deferred donors confirmed deferrable travel history. In the anonymous survey 0.3% of donors were non-compliant with the UK/France deferral.
Discussion:
Donors, particularly first-time ones, continue to be lost due to vCJD travel deferral, but most deferrals are correctly applied and non-compliance is rare. The application of a "stop date" reduced deferrals for UK/France travel, but it may be too early to see the full impact of the "stop date" for Western Europe.
