Evaluation of Zika Virus Inactivation in Whole Blood Via UV Irradiation and Photosensitizers

Authors

• Y He
• F Xu
• DE Scott
• J Vostal
• JL Reed

Abstract

Even in asymptomatic patients, Zika virus infection can produce viremia, with viral burdens in the blood potentially exceeding 10^6 copies/ml. Two cases of Zika virus transmission via blood donations from asymptomatic donors have been recently reported. Inactivation of Zika virus in transfusion products could potentially limit risk of virus transmission to patients. However, whether currently approved pathogen reduction (PR) methods can inactivate Zika virus in red cells or whole blood has not been demonstrated. To address this question, high-titer Zika virus stock (Cambodia 2011 strain, UTMB) was spiked into whole blood or plasma samples, and subjected to UV-A or UV-B treatments of 5 to 25 J/cm2. In some experiments, UV treatments were combined with photosensitizing compounds psoralen (UV-A) or vitamin B2 (UV-B). Virus recovery was quantitated by plaque assay developed in Vero cells. UV-B effectively inactivated Zika virus spiked into whole blood, although the efficiency of inactivation was much less than that observed in plasma (5.26 versus 9.58 log reduction). UV-B inactivation of Zika virus was enhanced approximately 0.5 log with the addition of vitamin B2. Psoralen with UV-A treatment demonstrated NLT 5.9 log reduction of Zika virus in plasma, however significant hemolysis with psoralen treatment alone precluded its use in whole blood. Efficiency of UV irradiation was decreased by passage through blood bag plastics. Our ongoing studies aim to further optimize UV irradiation parameters and blood container materials to maximize Zika virus inactivation. This information may accelerate use of Zika virus reduction technologies for cases of high-risk transfusions.

Scientific Focus Area: Virology

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