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

BACKGROUND: Middle 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 METHODS: MERS-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).

RESULTS: In 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.

CONCLUSION: Riboflavin 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.