BackgroundProtective respiratory face masks protect the nose and mouth of the wearer from vapor drops carrying viruses or other infectious pathogens. However, incorrect use and disposal may actually increase the risk of pathogen transmission, rather than reduce it, especially when masks are used by non-professionals such as the lay public. Copper oxide displays potent antiviral properties. A platform technology has been developed that permanently introduces copper oxide into polymeric materials, conferring them with potent biocidal properties.Methodology/Principal FindingsWe demonstrate that impregnation of copper oxide into respiratory protective face masks endows them with potent biocidal properties in addition to their inherent filtration properties. Both control and copper oxide impregnated masks filtered above 99.85% of aerosolized viruses when challenged with 5.66±0.51 and 6.17±0.37 log10TCID50 of human influenza A virus (H1N1) and avian influenza virus (H9N2), respectively, under simulated breathing conditions (28.3 L/min). Importantly, no infectious human influenza A viral titers were recovered from the copper oxide containing masks within 30 minutes (≤0.88 log10TCID50), while 4.67±1.35 log10TCID50 were recovered from the control masks. Similarly, the infectious avian influenza titers recovered from the copper oxide containing masks were ≤0.97±0.01 log10TCID50 and from the control masks 5.03±0.54 log10TCID50. The copper oxide containing masks successfully passed Bacterial Filtration Efficacy, Differential Pressure, Latex Particle Challenge, and Resistance to Penetration by Synthetic Blood tests designed to test the filtration properties of face masks in accordance with the European EN 14683:2005 and NIOSH N95 standards.Conclusions/SignificanceImpregnation of copper oxide into respiratory protective face masks endows them with potent anti-influenza biocidal properties without altering their physical barrier properties. The use of biocidal masks may significantly reduce the risk of hand or environmental contamination, and thereby subsequent infection, due to improper handling and disposal of the masks.

The masks, with or without features intended for enhancing comfort, provide protection against both small- and large-size pathogens. Importantly, the mask appears to be highly efficient for filtration of pathogens, including influenza and rhinoviruses, as well as the fine particulates (PM) present in aerosols that represent a greater challenge for many types of dental and surgical masks. This renders this individual-use N95 respiratory mask an improvement over the former types of masks for protection against a variety of environmental contaminants including PM and pathogens such as influenza and rhinoviruses.

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This chapter focuses on viral efficacy evaluations of silver ion (Ag+) formulations against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus associated with the COVID-19 pandemic and feline calicivirus (FCV), a surrogate for human norovirus. The chapter discusses the proposed mechanism of inactivation, with reference to some previously published articles. In addition, it discusses the background/current trend/future view of Ag+ products that have been used widely as surface/environment disinfectants in daily life all over the world. In efficacy studies performed by using the standardized ASTM E1052 methodology, it was found that Ag+ formulated with a low concentration (26% w/w) of ethanol displayed virucidal activity against SARS-CoV-2 and FeCV. These formulations might be useful for preventing the transmission of such viruses and limiting the outbreaks of emerging infectious diseases caused by coronaviruses and caliciviruses. To our knowledge, this is the first report describing the virucidal efficacy of an Ag+ formulation, evaluated by using the standardized ASTM E1052 methodology, for inactivating SARS-CoV-2. Some characteristics of Ag+-based virucides are discussed in this research report/minireview.