Inactivation of Middle East respiratory syndrome coronavirus (MERS-CoV) in plasma products using a riboflavin-based and ultraviolet light-based photochemical treatment

BACKGROUNDMiddle East respiratory syndrome coronavirus (MERS-CoV) has been identified as a potential threat to the safety of blood products. The Mirasol Pathogen Reduction Technology System uses riboflavin and ultraviolet (UV) light to render blood-borne pathogens noninfectious while maintaining blood product quality. Here, we report on the efficacy of riboflavin and UV light against MERS-CoV when tested in human plasma. STUDY DESIGN AND METHODSMERS-CoV (EMC strain) was used to inoculate plasma units that then underwent treatment with riboflavin and UV light. The infectious titers of MERS-CoV in the samples before and after treatment were determined by plaque assay on Vero cells. The treatments were initially performed in triplicate using pooled plasma (n=3) and then repeated using individual plasma units (n=6). RESULTSIn both studies, riboflavin and UV light reduced the infectious titer of MERS-CoV below the limit of detection. The mean log reductions in the viral titers were 4.07 and 4.42 for the pooled and individual donor plasma, respectively. CONCLUSIONRiboflavin and UV light effectively reduced the titer of MERS-CoV in human plasma products to below the limit of detection, suggesting that the treatment process may reduce the risk of transfusion transmission of MERS-CoV.