Impact of nationwide parvovirus B19 DNA screening and identification of transfusion‐transmitted infections

Background and Objectives Parvovirus B19 (B19V) testing is often not required to release blood components. However, the European Pharmacopoeia requires that plasma pools for fractionation contain no more than 10 4 IU/mL of B19V DNA. In France, pool B19 nucleic acid testing (NAT) screening was performed by Établissement Français du Sang since 2015. Since June 2024, positive pools are broken down into individual testing, allowing for the identification and management of infected blood donations. Materials and Methods B19V NAT is performed in pools of 96 donations (P96) with the DPX Parvo/hepatitis A virus assay (Roche). A P96 with a viral load >10 4 IU/mL B19V DNA is considered positive. All individual donations (IDs) testing reactive for B19V by ID‐NAT are excluded from plasma‐based medicinal products production, and the corresponding blood components are destroyed if not yet transfused. Results From June 2024 to June 2025, 99 of 2,627,678 donations (3.7/100,000) were B19V DNA positive. All blood components related to 90 donations were discarded. Of the remaining nine donations, 13 blood components (9 platelet concentrates [PCs] that had undergone pathogen reduction (PR) and four red blood cell [RBC] concentrates) were transfused before NAT results were obtained. Two B19V transmissions were reported in recipients (0.078/100,000 transfusions) after transfusion of 1 PR‐PC and 1 RBC unit. Conclusion B19V DNA testing for plasma intended for fractionation performed in blood services helps in avoiding transmissions by the related blood components, provided positive donations are detected prior to their transfusion. Delayed availability of results may result in transfusion‐transmitted B19V infection, which cannot prevented by current PR technology.