Impact of the exclusion of donors having stayed in the United Kingdom on the residual risk of HIV transmission by blood transfusion.

Background - One of the measures aimed at reducing the risk of transmission of the agent responsible for the new variant of Creutzfeldt-Jakob disease was to exclude blood donors having stayed in the United Kingdom between 198 0 and 1996. The objective of the study was to estimate the impact on the re sidual risk of HIV transmission of recruiting extra first-time donors to re place donors having stayed in the United Kingdom. Methods - The residual risk of HIV transmission due to donations made durin g the window period was estimated in all donations made in France during th e 3-year period 1996-1998 by a linear combination of residual risks in repe at donors and first-time donors. In repeat donors, the estimate is based on the incidence rate of HIV in this population and in first-time donors on t he "detuned assay" method. Seven simulations of the impact on the residual risk were made using various percentages of donors which would be excluded (from - 5 % to - 35 %). Results - In all donations made in France during the 1996-1998 period, the residual risk of HIV transmission was estimated at 0.70 per million donatio ns, which represents five to six donations made during the window period. I f all the donors who had stayed in the United Kingdom were excluded from th e donation (35 %) and replaced by first-time donors, the residual risk of H IV transmission would be increased from 0.70 to 0.86 per million donations. This increase of 24 % would represent one or two extra cases of post-trans fusion HIV infection over a 3-year period. Conclusion - The results of this study show that the exclusion of a large n umber of blood donors, replaced by first-time donors, would have a low but quantifiable impact on the residual risk of HIV transmission. This increase of risk was one of the factors that led to the decision of not excluding d onors having stayed in the United Kingdom between 1980 and 1996. (C) 2001 E ditions scientifiques et medicales Elsevier SAS.