Results of viral marker screening of unpaid blood donations and probability of window period donations in 1997

Background and Objectives: To monitor the safety of the blood supply and evaluate the potential benefits of additional measures, the likelihood of virus transmission must be assessed. The European Plasma Fractionation Association and its member organisations have therefore developed a surveillance system to monitor infection markers among unpaid blood and plasma donors. We report and analyse the results of this surveillance for 1997. Materials and Methods: Data from the screening of unpaid donations for anti-HIV, anti-HCV and HBsAg during 1997 were collected retrospectively by EPFA member organisations. We identified seroconverters and estimate the probability of window period donations. Results: Data included screening results from 11 million unpaid donations in Europe, the USA and Australia. Prevalence of viral markers varied, with marker rates from repeat donations in Europe and Australia bei ng significantly lower than in the USA. For first-time donations, in contrast, prevalence of HBsAg in the USA was within the ranges of those measured in Europe and Australia. Screening data of about 5 million European and 0.5 million Australian repeat donations were used to identify seroconverters. From the seroconverters that were detected among the European organisations, we estimated that 1 in every 2,323,778 repeat donations (range: 707,090-20,922,520) was made during the window period of anti-HIV screening. One in 620,754 (201,216-2,316,805) and 1 in 398,499 (155,209 to >1,088,511) repeat donations were made during the anti-HCV or HBsAg window period, respectively. Probabilities of window period donations in Australia were within the ranges of those measured in Europe. Conclusions: The collated surveillance data of 1997 illustrate the high degree of safety in blood and plasma products from unpaid donors. Copyright (C) 2000 S Karger AG, Basel.