title: The residual risk of transfusion-transmitted cytomegalovirus infection associated with leucodepleted blood components.
abstract: OBJECTIVE
  Cytomegalovirus poses a risk to transfusion safety as its transmission to an immunocompromised recipient may lead to significant clinical sequelae. Once infection is established, it is lifelong and generally asymptomatic. Strategies to reduce the risk of transfusion-transmitted CMV (TT-CMV) include donor serological testing and blood component leucodepletion to deplete the transmissible reservoir. We estimate the residual risk for non-CMV antibody screened, leucodepleted (LD-only) fresh blood components.
  
  
  METHODS
  We established an approach to estimate the risk of TT-CMV under various scenarios. We estimated the probability of an infectious component, for both red cells and platelets, as a function of the observed WBC filter failure rate and the probability that such a unit was also contaminated with infectious virus.
  
  
  RESULTS
  Using this model, the estimated combined residual risk of LD-only red cell and platelet units was very low, 1 in 13 575 000 (95%CI:1 in 1 344 167 000-1 in 1 730 000) as was the individual residual risk estimate for LD-only red cells, 1 in 7 790 000 (95%CI: 1 in 771 307 000-1 in 993 000) and LD-only platelets, where a zero risk was estimated (95%CI: 0-1 in 1 074 000).
  
  
  CONCLUSIONS
  We describe a novel approach to assess the residual risk of LD-only components. This can be applied generally using local data. Our risk estimate for LD-only blood components in Australia is below the threshold of 1 in 1 million, generally considered negligible. This provides a useful indicator of the relative safety of LD-only components to assist clinical decisions when serologically screened inventory is unavailable.
authors: Australian Red Cross Blood Service, Perth, WA, Australia.
authors: C R
authors: CR
authors: Seed
authors: Australian Red Cross Blood Service, Sydney, NSW, Australia.
authors: J
authors: J
authors: Wong
authors: Department of Clinical Haematology, Monash University, Melbourne, Vic., Australia.
authors: M N
authors: MN
authors: Polizzotto
authors: Australian Red Cross Blood Service, Brisbane, Qld, Australia.
authors: H
authors: H
authors: Faddy
authors: Australian Red Cross Blood Service, Perth, WA, Australia.
authors: A J
authors: AJ
authors: Keller
authors: Australian Red Cross Blood Service, Brisbane, Qld, Australia.
authors: J
authors: J
authors: Pink
mesh_terms: D000818:Animals; D016913:Blood Component Transfusion; D001782:Blood Donors; D001792:Blood Platelets / Q000166:cytology; D003587:Cytomegalovirus / Q000276:immunology; D003586:Cytomegalovirus Infections / Q000635:transmission*; D004912:Erythrocytes / Q000166:cytology; D006801:Humans; D007962:Leukocytes / Q000166:cytology; D051379:Mice; D012306:Risk
keywords: blood safety; leucodepletion; residual risk estimation; transfusion-transmissible infection