Inactivation of Human Coronavirus by FATHHOME’s Dry Sanitizer Device Rapid and Eco-Friendly Ozone-Based Disinfection of SARS-CoV-2

Background

The COVID-19 pandemic increased demand for effective, low-cost disinfection methods that could be used outside large hospital systems - in dental clinics, care homes, retail settings and by home carers. Many existing options rely on chemical disinfectants or heat-and-pressure sterilisation, which are not always practical for the volume of personal protective equipment (PPE) and everyday surfaces frontline workers need to decontaminate. This study examined whether a dry, ozone-based sanitising device could offer a faster, chemical-free alternative for inactivating a human coronavirus on common surfaces.

Study design

Researchers from the University of Nevada, Reno and Lawrence Berkeley National Laboratory tested a dry-ozone sanitiser manufactured by FATHHOME, Inc. Rather than using SARS-CoV-2 itself, they used HCoV-OC43, a related human coronavirus that can be handled at lower biosafety levels and is commonly used as a surrogate in disinfection research. Viral suspensions were applied to two types of surface: nonporous glass and porous N95 respirator material. The treated surfaces were exposed to ozone at concentrations of 20, 25 and 50 parts per million (ppm) for varying durations. Afterwards, the researchers measured viral RNA levels using quantitative reverse-transcription PCR (qRT-PCR) and tested remaining infectivity using cell culture and immunofluorescence assays. Each condition was run in duplicate across three independent experiments, and residual ozone on the treated materials was also measured.

Findings

Ozone exposure at 20 ppm for 10 minutes reduced infectious virus by 99.8-99.9% on both glass and N95 material. Increasing the dose to 25 ppm for 15 minutes achieved complete inactivation, with a reduction of more than six orders of magnitude (a greater than 6-log reduction) in infectious virus on both surface types. No residual ozone was detected on the treated materials once the sanitisation cycle had finished.

What the authors concluded

The authors concluded that the FATHHOME dry-ozone sanitising device could rapidly and effectively inactivate a human coronavirus on both porous and nonporous surfaces, without leaving chemical residue or requiring heat or pressure. They suggested this type of device could be a practical option for frontline workers and smaller operations - such as dental clinics, EMS, aged care facilities and hospitality settings - that need to decontaminate PPE and equipment but lack access to industrial-scale sterilisation systems.

Limitations of this study

This was a laboratory (in vitro) study using HCoV-OC43 as a surrogate for SARS-CoV-2, rather than testing SARS-CoV-2 itself, so the results may not translate exactly to the pandemic virus. The experiments were run at a small scale (duplicate samples across three repeats), and the study did not assess whether repeated ozone exposure affects the long-term integrity or performance of N95 respirator material over multiple sanitisation cycles. Real-world conditions - including variable humidity, surface soiling and device placement - were not tested. It should also be noted that one of the four authors is employed by FATHHOME, Inc., the manufacturer of the device evaluated in this study. This is a relevant commercial conflict of interest for readers to weigh when interpreting the findings, even though the published paper states the authors declare no conflict of interest.