Figure 1.
Pattern of use of ET instruments and natural history of sCJD transmission.
a–In this example of ET, 6 files were used in an infectious sCJD patient. The history of each file is represented horizontally from left to right. At the time of ET (•), the total number of future reuses varies from one instrument to the other (here between 8 and 10). For example, instrument 4 was used for the first time on the infectious sCJD patient, and will be reused 9 times in subsequent patients. In contrast, instrument 6 is never reused after being contaminated. b–Flow chart of sCJD transmission and natural history in our model. The sCJD incubation period is divided into three phases: I, the infected individual is neither infectious nor symptomatic, II, the patient becomes infectious, but remains asymptomatic: this is the only period when iatrogenic transmission is possible. III, the patient is symptomatic and CJD has been diagnosed so that the patient MUST be treated with single-use instruments and will not infect others.
Table 1.
The 10 components considered in the estimation of risk of iatrogenic sCJD transmission.
Figure 2.
Individual risk assessment of sCJD transmission during ET, using dose–effects functions ϕ1 ( blue) and ϕ2 ( green).
A: median (vertical line within the box), the 95% CI (T bars), and the 25th–75th percentiles (left and right borders of the box). B: risks of iatrogenic mortality associated with other procedures.
Figure 3.
Population risk assessment of sCJD transmission during ET, using dose–effects functions ϕ1 ( blue) and ϕ2 ( green).
See the legend to figure 2 for the description of the box plots. The vertical line passing through both plots is the epidemic threshold (R>1).