Ultraviolet C light efficiently inactivates nonenveloped hepatitis A virus and feline calicivirus in platelet concentrates

BACKGROUND Nonenveloped transfusion‐transmissible viruses such as hepatitis A virus (HAV) and hepatitis E virus (HEV) are resistant to many of the common virus inactivation procedures for blood products. This study investigated the pathogen inactivation (PI) efficacy of the THERAFLEX UV‐Platelets system against two nonenveloped viruses: HAV and feline calicivirus (FCV), in platelet concentrates (PCs). STUDY DESIGN AND METHODS PCs in additive solution were spiked with high titers of cell culture–derived HAV and FCV, and treated with ultraviolet C at various doses. Pre‐ and posttreatment samples were taken and the level of viral infectivity determined at each dose. For some samples, large‐volume plating was performed to improve the detection limit of the virus assay. RESULTS THERAFLEX UV‐Platelets reduced HAV titers in PCs to the limit of detection, resulting in a virus reduction factor of greater than 4.2 log steps, and reduced FCV infectivity in PCs by 3.0 ± 0.2 log steps. CONCLUSIONS THERAFLEX UV‐Platelets effectively inactivates HAV and FCV in platelet units.