Supplementary Material for: PARVOVIRUS B19 INFECTION AFTER TRANSFUSION OF A PATHOGEN-REDUCED PLATELET CONCENTRATE: A CASE REPORT

Introduction
Parvovirus B19 (B19) exhibits moderate resistance to the pathogen reduction methods employed during the production of platelet concentrates. In Switzerland, nucleic acid testing (NAT) for B19 is conducted for plasma fractionation; however, its results are not mandatory for the release of blood products.

Case Presentation
We describe a case of B19 infection in an immunosuppressed, seronegative patient who received a pooled platelet concentrate treated with UVA light and amotosalen. Although the patient remained clinically asymptomatic, the infection was confirmed through laboratory findings, including rising viremia, seroconversion, and mild hematologic changes. We report the clinical course in detail, including treatments and co-medications. Phylogenetic analysis of the viral genome confirmed a direct link between the transfusion and the infection.

Conclusion
This case highlights that, similar to other infectious agents, Parvovirus B19 can be transmitted through pathogen-reduced blood products. It emphasizes the necessity for established surveillance procedures to detect such transmissions and ensure timely clinical intervention in affected patients.