Established robustness of viral filtration and existing
knowledge gaps
As previously stated, the broadly accepted mechanism of virus removal by
viral filtration is size based sieving which is relatively unaffected by
physiochemical characteristics of the viral species. Decades of
scale-down scientific studies with viral filters support the robust and
effective removal of viruses under varying typical and worst-case
process conditions. Parameters typically evaluated in viral filter
studies include feed pressure, differential pressure, product loading,
flow pausing, or solution conditions (e.g. pH, ionic strength, protein
concentration, etc.). Existing published filtration studies are
summarized in brief in sections below.