Intra-family differences in efficacy of inactivation of small, non-enveloped viruses

The use of specific model viruses for validating viral purification process steps and for assessing the efficacies of viral disinfectants is based, in part, on the assumption that viral susceptibilities to such treatments will be similar for different members, including different genera, within a given viral family. This assumption is useful in cases where cell-based infectivity assays or laboratory strains for the specific viruses of interest might not exist. There are some documented cases, however, where exceptions to this assumption exist. In this paper, we discuss some of the more striking cases of intra-family differences in susceptibilities to inactivation steps used for downstream viral purification steps in biologics manufacture (e.g. heat inactivation, low pH, and guanidinium hydrochloride inactivation) and to specific viral disinfectants (e.g. alcohols, hydrogen peroxide, and quaternary ammonium-containing disinfectants) that might be employed for facility/equipment disinfection. The results suggest that care should be taken when extrapolating viral inactivation susceptibilities from specific model viruses to different genera or even to different members of the same genus. This should be taken into consideration by regulatory agencies and biologics manufacturers designing viral clearance and facility disinfection validation studies, and developers and evaluators of viral disinfectants.