A review of the test methods used to establish virucidal activity

Testing the efficacy of disinfectants has been the domain of bacteriologists for many years. Recently interest has grown in the virucidal effects of disinfectants, due to increased awareness of viral infections and concern for possible cross-infection. Findings have demonstrated significant differences in the susceptibility of certain viruses, particularly non-enveloped viruses, e.g. enteroviruses, to disinfectants compared to some bacteria. For example Escherichia coli and herpes simplex virus are inactivated by 20% isopropyl alcohol (IPA) whereas Staphylococcus aureus requires > or = 50% and poliovirus is not inactivated by IPA. Currently there is little or no standardization in the methods used for the determination of virucidal activity in suspension, or on hands and surfaces. Methods in use in Europe and the USA will be reviewed and their relevance to the clinical situation discussed.