Residual infectious risks in blood transfusion

Blood transfusion in developed countries is extremely safe. However, a residual risk remains of infectious donations slipping through, because of imperfect donor selection and the diagnostic window period. A myriad of regulations and safety measures is in place to guarantee the high level of safety. The boundary between risks that should be covered by safety measures, and residual risks that are acceptable, is unclear. This thesis focuses on the yield of safety measures that cover small infectious risks.
Occult HBV infected donors and previous donations from seroconverting donors may be infectious. The risk of transmission was assessed by lookback procedures.
Transfusion transmissible infections (TTIs) are more common among new donors than repeat donors, as a result of the accumulation of chronic, yet undiagnosed infections. Because of the possibility of acute infections among new donors (eg. among ‘test seekers’), the value of predonation screening without actual donation was assessed.
Temporary geographical deferral for donors who travelled to countries where (re)emerging infectious agents are prevalent is commonly practiced. The yield of donor deferral after travelling, by estimating the number of infected donors returning from affected areas, was assessed and the consequences for donor availability were calculated. The European Up-Front Risk Assessment Tool (EUFRAT) quantifies the transfusion transmission risk of donations from donors returning from affected areas where an emerging infectious disease is prevalent. An EUFRAT estimation of dengue infections among Dutch donors travelling to Suriname or the Dutch Caribbean was validated with the actual number of dengue infections detected among Dutch travellers.