Preventing Transmission of Chagas Disease in the U.S. Blood Supply: A Cost-Effectiveness Analysis of Testing Blood Bank Donations

Background: Chagas Disease is a parasitic infection that affects people living in poor, rural areas of the Americas. Though Chagas is not endemic to the U.S., increased attention on immigration from Latin America to the U.S. coupled with the availability of a highly effective assay highlight the need for testing of the blood donations for Chagas, which may be transmitted through transfusion. Currently, blood banks are not required to test for Chagas.

Methods: To estimate incremental cost-effectiveness of blood bank testing and screening strategies for Chagas, a cost-effectiveness analysis with a decision tree model with a 20-year time horizon is used. Data is taken from peer-reviewed literature. The interventions include: 1) testing all blood donations, 2) verbal screen with ELISA testing for those with a positive screen, and 3) testing new donors only. Base-case and sensitivity analyses are conducted.

Results: In the base-case analysis, Test All averted 20 additional cases over Screen and Test, but at a cost of $3.6 million per additional case averted. Test New Donors resulted in an additional 14 disease cases compared to Screen and Test and with had the lowest costs of all alternatives. The sensitivity analysis is most sensitive to whether or not a negative verbal screen was obtained and slightly sensitive to the probability for high risk of transmission.

Conclusion: Both Screen and Test and Test All improve over the standard of Test New Donors in the number of cases averted, however, both are cost-prohibitive at thresholds of $1 million per case averted.