Enveloped Virus Inactivation on Personal Protective Equipment by Exposure to Ozone

Abstract

Ozone is a highly oxidizing gas easily generated from atmospheric oxygen with inexpensive equipment and is commonly used for the disinfection of municipal water, foods, and surfaces. We report tests of the ability of ozone to inactivate enveloped respiratory viruses (influenza A virus and respiratory syncytial virus), chosen as more easily handled surrogates for SARS-CoV-2, on N95 respirators and other personal protective equipment (PPE) commonly used in hospitals. At 20 ppm, an ozone concentration easily achieved by standard commercial equipment, the viruses were inactivated with high efficiency as long as the relative humidity was above a threshold value of approximately 50%. In the absence of humidity control, disinfection is more variable and requires considerably longer exposure under relatively dry conditions. This report extends the observations of a previous publication (http://doi.org/10.1080/01919510902747969) to hospital-relevant materials and provides additional details about the relationship of humidity to the antiviral activity of ozone. Home CPAP disinfection devices using ozone can provide effective results for individuals. Ozone did not appear to degrade any of the materials tested except for elastic bands if strained during treatment (such as by the pressure exerted by stapled attachment to N95 respirators). The filtration efficiency of N95 respirator material was not compromised.

A systematic review of mask disinfection and reuse for SARS-CoV-2 (through July 10, 2020)

“…In the eight Phi6 results 27,40,56,72 , moist heat at 72-82°C for 30 minutes achieved <6 or >6 log reduction but inaccurate humidity readings occlude results, 7% aerosolized hydrogen peroxide had >6 log reductions with 30 minute exposure, and VHP at 16 gram/minute had >4 log after 30-40 minute exposure time; please note UVGI for one minute had only 1.5 log reduction. In the six IAV samples 41,43,56,63 , ozone removed 1-2 log after 40 minute exposure to 20 ppm, and moist heat and MGS achieved >3 log reduction after 30 minutes exposure to 60-82C moist heat for 30 minutes and 2 minute exposure to MGS.…”

Inactivation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by gaseous ozone treatment

“…Studies of disinfection with surrogate viruses used ozone concentrations in the range of 10 ppm to 20 ppm for shorter periods [ 2 , 3 ]. Using higher ozone concentrations for shorter periods may make the process more logistically feasible in busy hospitals where short room turnaround times are required.…”

“…Recently, Blanchard et al reported ozone disinfected influenza A virus and respiratory syncytial virus that would serve as a reasonable surrogate for SARS-CoV-2 [ 2 ]. These results suggested that ozone has an effect on SARS-CoV-2, as we have demonstrated in this study.…”

Could ozone be an effective disinfection measure against the novel Coronavirus (SARS-CoV-2)?

“…1 ). Recently, it was reported that ozone treatment can be also a widely accessible and effective method for the disinfection of personal protective equipment (PPE) for both healthcare workers and patients for safe re-use in times of shortage [ 11 ].…”