Volume 13, Number 1—January 2007
Research
Blood Transfusion and Spread of Variant Creutzfeldt-Jakob Disease
Table 1
Summary of input parameters for the model*
Parameters | Description | Source |
---|---|---|
Age-specific mortality rates | U-shaped, with minimum at age 10. | Federal Statistical Office of Germany |
Donor recruitment | Donors ages 18–67 y. Maximum recruitment rate at age 18, lower plateau ages 25–50; further decrease until age 67. | Age-distribution of first-time donors at DRK Blood Service and age structure in population |
Proportion of donors | 3% of population. | DRK Blood Service West |
Duration as active donor | Donors ages 18–40 y, mean duration as active donor 10–14 y, decreases linearly to 0. | Age distribution of active donors at DRK Blood Service West, by age at first donation |
Risk of receiving transfusions | Bimodal, with peaks for newborns and aged persons. Multiple transfusions possible. | Data collected from 4,867 patients March 2003, University Hospital Essen, Germany |
Transfusion-associated risk for death | Increases according to a sigmoid function, ≈17% at birth to ≈48% in old age. For those with transfusion-associated risk for death, life expectancy is ≈2.5 years at birth and decreases to ≈0.5 y in old age. | Follow-up of ≈3,000 transfusion recipients for ≈7.5 y in Newcastle, UK (4) |
Alimentary infection | Constant over an initial period of 10 y. | Arbitrary assumption |
Incubation period† | Gamma distributed with mean 16 y, SD 4 y. Sensitivity analysis with mean = 50 y and same coefficient of variation. | Models fitted to the UK incidence of vCJD (5,6) |
Donor exclusion | Either 0 or 95% of those with transfusion history. | Arbitrary assumption |
*DRK, German Red Cross; SD, standard deviation; vCJD, variant Creutzfeldt-Jakob disease.
†Time between infection and death, i.e., duration of infection.
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