**Abstract**

Hydrogen peroxide is a common antiseptic and disinfectant that is effective against both enveloped and non-enveloped viruses, and it is sometimes used as a fumigant to achieve disinfection of indoor spaces. While it is effective as a fumigant, it cannot be used continuously, allowing for possible recontamination of the treated spaces between applications. A novel method of hydrogen peroxide application, termed "Dry Hydrogen Peroxide" (DHP™), generates molecules of hydrogen peroxide in a true gas state at concentrations low enough to be used continuously within spaces occupied by humans. This chapter explores the efficacy of DHP against a variety of viruses, both enveloped and non-enveloped. On surfaces, DHP achieved a ≥ 99.8% reduction (≥2.62 log10 inactivation) of infectious H1N1 influenza A (enveloped) compared to the control condition within 1 hour, and it achieved a 99.8% reduction (2.62 log10 inactivation) of infectious feline calicivirus (non-enveloped) compared to the control condition within 6 hours. DHP also achieved a 99.8% reduction 2.62 log10 inactivation) of airborne MS2 bacteriophage (non-enveloped) within 1 hour in comparison to the control condition. These inactivation efficacy results, combined with results from recent clinical studies, indicate that DHP represents an effective adjunct technology that can mitigate viral load between intermittent applications of other types of disinfectants.

**Keywords:** viral inactivation, dry hydrogen peroxide, disinfectant, hydroxyl radical, biocidal action
