The Cost-Effectiveness of Screening the U.S. Blood Supply for West Nile Virus

4 October 2005 | Volume 143 Issue 7 | Pages 486-492

Background: The spread of West Nile virus across North America and evidence of transmission by transfusion prompted the U.S. Food and Drug Administration to encourage the development of methods to screen the blood supply.

Objective: To assess the cost-effectiveness of nucleic acid amplification testing for West Nile virus in the U.S. blood supply.

Design: Markov cohort simulation.

Data Sources: Outcome probabilities estimated from nucleic acid testing done for West Nile virus in 2003, data from the Centers for Disease Control and Prevention, and published literature. Costs were taken from an economic study of West Nile virus infection and from estimated test costs.

Target Populations: Transfusion recipients, 60 years of age or older, with and without underlying immunocompromise.

Time Horizon: Lifetime.

Perspective: Societal.

Interventions: The authors compared 6 strategies, taking into consideration minipool (pools of 6 to 16 donations) versus individual donation testing, and the geographic and seasonal nature of West Nile virus activity.

Outcome Measures: Costs and effects of each strategy based on the prevention of transfusion-transmitted West Nile virus.

Results of Base-Case Analysis: The cost-effectiveness of annual, national minipool testing was $483 000 per quality-adjusted life-year (QALY), whereas the cost-effectiveness of annual, national individual donation testing was $897 000/QALY. The cost-effectiveness of targeted individual donation testing in an area experiencing an outbreak coupled with minipool testing elsewhere was $520 000/QALY.

Results of Sensitivity Analysis: In 1-way analyses, the most important influences were the prevalence of West Nile virus and the cost of minipool testing and individual donation testing. The 95% range of results from probabilistic sensitivity analysis for targeted individual donation testing was $256 000 to $1 044 000/QALY.

Limitations: The outcomes of West Nile virus infection were based on data from the general population rather than from the population who received transfusions. The results are most useful in the context of geographically focused outbreaks of West Nile virus infection.

Conclusions: Using targeted individual donation testing to interdict blood donations that are positive for the West Nile virus is relatively cost-effective but is highly dependent on West Nile virus prevalence.

Editors' Notes Context Since June 2003, U.S. regulations have required blood banks to screen donated blood for West Nile virus using nucleic acid amplification tests. The cost-effectiveness of such screening is unknown. Contribution The most cost-effective strategy was annual, national minipool testing, which pools 6 to 16 donations and tests for West Nile virus. Individual donations are tested only when the pool tests positive. This strategy cost $483 000 per quality-adjusted life-year saved, substantially more than society pays for other health care interventions. Implications Eradicating West Nile virus from the blood supply is an inefficient use of resources. –The Editors

 

Author and Article Information

From the Blood Systems Research Institute, University of California, San Francisco, and Centers for Disease Control and Prevention, San Francisco, California; and National Center for Infectious Diseases, Fort Collins, Colorado.

Grant Support: By an unrestricted grant from Blood Systems Foundation.

Potential Financial Conflicts of Interest: Employment: B. Custer (Blood Systems, Inc.), M.P. Busch (Blood Systems, Inc.); Consultancies: M.P. Busch (Chiron Corp., Roche, Gen-Probe); Grants received: B. Custer (Blood Systems Foundation), M.P. Busch (Chiron Corp., National Institutes of Health, Centers for Disease Control and Prevention).

Requests for Single Reprints: Brian Custer, PhD, Blood Systems Research Institute, 270 Masonic Avenue, San Francisco, CA 94118-4417; e-mail, bcuster{at}bloodsystems.org.

Current Author Addresses: Dr. Custer: Blood Systems Research Institute, 270 Masonic Avenue, San Francisco, CA 94118-4417.

Dr. Busch: Department of Laboratory Medicine, University of California, San Francisco, c/o Blood Systems Research Institute, 270 Masonic Avenue, San Francisco, CA 94118-4417.

Dr. Marfin: San Francisco International Airport, Quarantine Station, Centers for Disease Control and Prevention, U.S. Public Health Service, Department of Health and Human Services, San Francisco, CA 94128-0548.

Dr. Petersen: Division of Vector-Borne Infectious Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, U.S. Public Health Service, Department of Health and Human Services, Fort Collins, CO 80522-2087.

Author Contributions: Conception and design: B. Custer, M.P. Busch, A.A. Marfin, L.R. Petersen.

Analysis and interpretation of the data: B. Custer, M.P. Busch, A.A. Marfin, L.R. Petersen.

Drafting of the article: B. Custer, A.A. Marfin, L.R. Petersen.

Critical revision of the article for important intellectual content: B. Custer, M.P. Busch, A.A. Marfin, L.R. Petersen.

Final approval of the article: B. Custer, M.P. Busch, A.A. Marfin, L.R. Petersen.

Provision of study materials or patients: M.P. Busch.

Statistical expertise: B. Custer.

Obtaining of funding: B. Custer, M.P. Busch.

Administrative, technical, and logistic support: B. Custer.

Collection and assembly of data: B. Custer, M.P. Busch.