**6. Conclusions**

In this chapter, we have reviewed the current state of the science regarding the virucidal efficacy of microbicides for viruses causing the current WHO Priority List diseases. By definition, information might be expected to be minimal for at least some of these viruses, hence the need for encouraging additional research. Not surprisingly, the efficacy of microbicides for inactivation of certain of the lethal (BSL-4) viruses, especially the paramyxoviruses Nipah virus and related henipaviruses and the bunyaviruses CCHFV and RVFV, was found to be poorly characterized. The need for further research into the virucidal efficacy of microbicides for the arenavirus (Lassa virus) and the filovirus (Marburg virus) is also indicated by the relative paucity of empirical data identified during the review. For the beta-coronaviruses (SARS-CoV, SARS-CoV-2, and MERS-CoV), the filovirus (Ebola virus), and the flavivirus (Zika virus), the available knowledge base for virucidal efficacy of microbicides appears to be adequate for verifying the predicted efficacy based on the hierarchy of virus susceptibility to microbicides.

It is hoped that this discussion will provide assurance to the IPAC community of the empirically determined virucidal efficacy of targeted hygiene agents against SARS-CoV-2 for use during the current SARS-CoV-2/COVID-19 pandemic. SARS-CoV-2 is evolving continuously, and the emerging mutational variants are being monitored for impact on previously vaccinated and non-vaccinated individuals. The microbicides displaying virucidal efficacy against SARS-CoV-2, MERS-CoV, and SARS-CoV should display equivalent efficacy against emerging mutational variants [97], including the Delta, Omicron, and other variants. Current Variants of Interest (VOI) may become Variants of Concern (VOC) in the future, and the

appropriate CDC/WHO websites [91, 92] should be consulted to keep up-to-date regarding the mutational variants of SARS-CoV-2. The information presented in this chapter also should be useful for the IPAC community as it considers nonpharmaceutical interventions for the other Priority List diseases in addition to SARS-CoV-2.
