by Gail Sofer, BioReliance Dorothy C. Lister, and Jeri Ann Boose Smallest of the microorganisms, viruses depend on other cells ? like those used by biopharmaceutical manufacturers ? for reproduction. And viruses and drug products are idiosyncratic: Both the inactivation process and the product strongly influence the successful outcome. In this conclusion to the virus inactivation series, model ivruses are used to represent single- and double-stranded DNA and RNA viruses, to enable you to reach conclusions about effective inactivation methods for a range of viruses.