Viral reduction techniques: types and purpose

Viral reduction techniques help assure the highest level of plasma-product safety that is possible using today's technology. However, worldwide travel and changing demographics could bring new pathogens into focus and thus require plasma-product manufacturers to be continually vigilant in their efforts to refine current reduction techniques and develop and apply new methods. This review focuses on all the currently used viral reduction techniques, why viral reduction continues to be important (even with the use of polymerase chain reaction techniques to improve plasma screening), and possible future directions for viral reduction. When exploring current approaches, including heat treatment (especially pasteurization), solvent/detergent, pH changes, and ultrafiltration, this review also includes (where applicable) the negative impact of these techniques on product integrity and/or viruses not destroyed. Other techniques (eg, chromatography) and the fractionation steps relevant in the production of selected plasma products may also impart viral reduction and are briefly assessed. Relying on an extensive review of current online and printed literature, this article also discusses the current US and European guidelines and regulations that impact viral reduction techniques. This information includes emphasis on the recommendation to use at least 2 reduction techniques (each with a different mode of action) for each plasma product so as to substantially reduce both enveloped and nonenveloped viruses. The approach to validation studies and results from specific studies are reviewed, and future approaches for viral reduction are described.