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Potential Effects of Additional Donor Deferrals on the U.S. Blood Supply

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  1. Potential Effects of Additional Donor Deferrals on the U.S. Blood Supply Hong Yang, Ph.D. Office of Biostatistics and Epidemiology FDA-Center for Biologics Evaluation & Research Transmissible Spongiform Encephalopathies Advisory Committee Meeting August 1 2011,Gaithersburg MD

  2. Background─ vCJD Risk in Saudi Arabia (SA) 3 vCJD cases attributed to residence in SA have been reported Information on vCJD risk in SA is limited vCJD risk likely associated with exposure to bovine spongiform encephalopathy (BSE) agent during extended residence in SA during years 1980-1996 Major risk likely from imported beef, feed materials, and live cattle from UK ~10% beef consumed in SA during 1980-1996 imported from UK US military base in SA participated UK Beef Program prior to 1990 (possibly significant amount of beef imported from UK) Risk associated with imported beef from Europe unknown Indigenous BSE risk in SA unknown

  3. Background─ FDA’s Assumptions and Considerations for Donor Deferral FDA’s Assumptions vCJD risk in US military bases in SA similar to risk in military bases in Europe vCJD risk in SA similar to risk in countries in western Europe except the risk in SA ended at 1996 FDA’s Considerations Indefinitely defer US donors, who spend >6 months cumulatively in SA as military personnel during the years 1980-1996 otherwise spent > 5 years cumulatively in SA during the year 1980-1996

  4. Four Potential at-risk Groups Affected (1) US Military Personnel deployed to SA, 1980-1996 • UK Beef Program • 1 year deployment • Negligible number of dependents • Most currently donating in civilian blood program (2) US Military Contractors in SA, 1980-1996 • Share same risk as Saudi residents • Time spent ranges from 6 months to 1 year (3) US Non-Military Contractors in SA, 1980-1996 • Time spent ranges from months to >10 years (4) Saudi Arabian Immigrants who have come to US since 1985 • Immigrants prior to 1985 not exposed or stayed <5 years during years 1980-1996

  5. Population to be Deferred (1):US Military Personnel • Data: • Number US troops deployed to SA for > 6 months during years 1980-1996 (NM(1980-1996)): ~ 600,000 (US Department of Defense) • Percent would be deferred under currently implemented FDA recommendations (Percdf): 30%(US Department of Defense) • Model Estimate: • Number Military Personnel to be deferred (NDM) NDM= NM(1980-1996)x(1- Percdf)

  6. Population to be Deferred (2): US Military Contractors • Data: • Number US Contractors hired by military to work in SA 1980-1996 (NMC(1980-1996)): ~200, 000(US Department of Defense) • Assumption: • None have cumulative stay for > 5 years (US Department of Defense) • Model Estimate: • Number Military Contractors to be deferred (NDMC) NDMC = 0

  7. NNMC-ann x 17 yrs (from 1980 to 1996) x P>5 yr NDNMC = Tavg Population to be Deferred (3): US Non-Military Contractors • Data: • 36,000 registered US citizens in SA in 1999 (US State Department) • Represents annual number US Non-military Contractors during years 1980-1996 (NNMC-ann) • Assumptions Average Time Spent (Tavg): 4 years Percent of stay for > 5 years (P>5 yr): 30% • Model Estimate: • Number Non-military Contractors to be deferred (NDNMC)

  8. Populations to be Deferred (4): Saudi Arabian Immigrants to US • Data: • Saudi-born immigrants during years 1989-2010 (US Department of Homeland Security) • Average annual number immigrants per year (NI-ann): 920 • Assumption: All immigrants since 1985 stayed in Saudi Arabia for > 5 years during years 1980-1996 • Model Estimate: • Number Immigrants to be deferred (NDI) NDI = NI-ann x 27 yrs (from 1985 to 2011)

  9. Results: 1Impact of Donor Deferral for Time Spent in SA on Loss of Blood Donors and Donations 1The results are approximation of loss of donors and donations (confidence intervals of estimates were not obtained) 2Assumption ― 5% donation rate (US Census 2009, HHS 2007) 3Assumption ― 1.7 donations per person per year (HHS 2007)

  10. Uncertainties • Limited information for US Non-Military Contractors • Lack of data on annual number of US Non-Military Contractors in SA during 1980-1996 • Available data for 1999 only • Not all US citizens in SA had registered with US Embassy • Lack of data on time spent • Varied by employment from months to >10 years • Sensitivity analysis was conducted to estimate the impact of uncertainties on the estimated loss of donations • Data on Saudi-born Immigrants do not include immigrants who were non-Saudi nationals • Uncertainty expected to have small impact on estimates of total loss of donors and donations from all groups

  11. Sensitivity Analysis:Alternative Assumptions on Annual Number and Time Spent of US Non-Military Contractors

  12. Results of Sensitivity Analysis ― Impact of Uncertainties on Data of US Non-Military Contractors on Estimated Donations Lost

  13. Conclusions • Additional deferral for time spent in SA may results in a total loss of approximately 25,000 donors and 42,000 donations every year from groups of US Military Personnel, US Non-military Contractors and Saudi Arabian Immigrants • The impact on US blood supply predicted to be small; the loss of donors and donations are approximately 0.2% of current donors and donations • Uncertainty of the data for Non-Military Contractors predicted to have small impact on estimated loss of blood donations

  14. Acknowledgments Steven Anderson, OBE David M. Asher, OBRR Jay Epstein, OBRR Luisa Gregori, OBRR Melissa Greenward, OCTGT Pedro Piccardo, OBRR Ginette Michaud, OBRR Jennifer Scharpf, OBRR

  15. Alternative Policy Option: 6-month Deferral for All Donors Alternative recommendations: Permanently defer US donors with a history of residence in SA for cumulative stay >6 months during 1980-1996 Populations to be deferred: • 60% US Military Personnel, 1980-1996 • 90% total US military personnel stayed > 6months • 30% military personnel have already been deferred • All US Military Contractors, 1980-1996 • All US Non-Military Contractors, 1980-1996 • All Saudi Arabian Immigrants to US since 1980

  16. Results ― Estimate of Loss of Blood Donors and Donations under Alternative Policy Option