A critical review on the inactivation of surface and airborne SARS-CoV-2 virus by ozone gas

COVID-19 pandemic has created chaos in almost every walk of life. The harsh impact of the disease is mainly rooted to the rapid and easy spread of SARS-CoV-2 virus through airborne and fomite routes. Thus, disinfection of contaminated surfaces and air is important to hamper COVID-19 disease transmission. Ozone being a potent gaseous disinfectant has been utilized to inactivate a wide-range of viruses and has more recently gained interest in the inactivation of SARS-CoV-2. This article critically reviews the current state-of-knowledge on disinfection of surface-adhered and airborne SARS-CoV-2 by ozone. The transmission and survival characteristics of SARS-CoV-2 alongside the specificity of ozone inactivation process are reviewed. Distinct focus is then given to reviewing the status of ozone inactivation of surface-adhered and airborne SARS-CoV-2 in terms of experimental investigations, kinetics, and influence of the operational factors on the inactivation process. Ozone inactivation of SARS-CoV-2 is compared to other enveloped viruses, and the challenges and future prospects of ozone inactivation of SARS-CoV-2 are also addressed. © 2022 The Author(s). Published with license by Taylor & Francis Group, LLC.

Applicability of on-site disinfection of personal protective equipment by ozone gas.

On-site disinfection techniques are beneficial during a pandemic when there is a marked shortage of personal protective equipment (PPE), as experienced during the coronavirus disease 2019 outbreak. Ozone gas has been considered an alternative on-site disinfectant during a pandemic because it has antimicrobial activities, can be produced from air by electricity without the need for storage, and can be easily deactivated after use. However, ozone gas might become distributed at the lower layer because it has a larger molecular weight than air. This study aimed to reveal the applicability of ozone gas for the on-site disinfection of PPE. The lockers meant for changing dresses were used as ozone gas exposure boxes, and the distribution of ozone was assayed. Considering that the determined ozone levels were not consistent in the types of ozone analysers, we studied the chemical and biological activities of ozone, which were evenly detected in the locker. The gown in the locker was also uniformly exposed to ozone. Results showed that ozone gas could be used for the on-site disinfection of PPE in a closed box, such as a locker. This finding is valuable during a pandemic when PPE is in short supply.

Inactivation of multiple human pathogens by Fathhome's dry sanitizer device: Rapid and eco-friendly ozone-based disinfection.

SARS-CoV-2 spread rapidly, causing millions of deaths across the globe. As a result, demand for medical supplies and personal protective equipment (PPE) surged and supplies dwindled. Separate entirely, hospital-acquired infections have become commonplace and challenging to treat. To explore the potential of novel sterilization techniques, this study evaluated the disinfection efficacy of Fathhome's ozone-based, dry-sanitizing device by dose and time response. Inactivation of human pathogens was tested on non-porous (plastic) surfaces. 95.42-100% inactivation was observed across all types of vegetative microorganisms and 27.36% inactivation of bacterial endospores tested, with no residual ozone detectable after completion. These results strongly support the hypothesis that Fathhome's commercial implementation of gas-based disinfection is suitable for rapid decontamination of a wide variety of pathogens on PPE and other industrially relevant materials.

Efficiency evaluation of ozone gas concentration generation by commercial ozone generator for disinfection in residential buildings

This article aims to present the efficiency evaluation of the ozone gas concentration generation by the commercial ozone generator for disinfection in residential buildings during the COVID-19 pandemic. The objectives of the research are 1) to evaluate the efficiency of the ozone gas concentration generation by the ozone generator available in the market;and (2) to determine its appropriateness. The 2 gram/hour ozone generator was placed near an air-conditioner for 60 minutes following the instructions of the manufacturer. Then, the ozone concentration measuring devices were developed using the Winsen® ZE14 ozone sensor, which display the results in LCD screen, save them in a micro-SD card in the form of an Excel file (.xlsx). The devices were then placed at 3 positions;4 meters, 8 meters, and 12 meters of the generator. Finally, the data of the ozone concentration collected from each position was processed and analyzed. The results revealed that (1) the 2 gram/hour commercial ozone generator was able to neutralize the pathogens (0.5 ppm in 5 minutes);and (2) the disinfection was appropriate for the 348 m3 room. Using it in larger room reduces its efficiency of disinfection. In conclusion, it is crucial to select the generator by considering its capacity and the size of the room for the highest efficiency according to the standards. The generator can be used assuredly and efficiently to disinfect and reduce the risk of infection. © 2022 IEEE.

Ozone gas applied through nebulization as adjuvant treatment for lung respiratory diseases due to COVID-19 infections: a prospective randomized trial.

The objective of this study was to provide lung disinfection by nebulizing ozone gas with distilled water and olive oil for patients who have clinical symptoms due to coronavirus disease 2019 (COVID-19). The study attempted to reduce the viral load of COVID-19 in the lungs of patients, to provide a faster response to medical treatment. Between August 2020 and September 2020, 30 patients who met the study criteria were prospectively evaluated. There were 2 groups with 15 patients in each group: patients in control group were not treated with ozone and only received standard COVID-19 treatment; patients in ozone group received lung disinfection technique with ozone and standard COVID-19 treatment. A statistically significant difference was found in the length of stay in hospital, change in C-reactive protein, polymerase chain reaction results after 5 days, and computed tomography scores between two groups. There was no statistically significant difference in D-dimer, urea, lactate dehydrogenase, lymphocyte, leukocyte, and platelet between two groups. According to the data, we think that the lung disinfection technique applied with ozone inhalation reduces the rate of pneumonia in COVID-19 patients and makes the patients respond faster to the treatment and become negative according to the polymerase chain reaction tests. The study was approved by the Ethical Committee of the Istanbul Medipol University Clinical Trials (approval No. 0011) on July 2, 2020.

CORonavirus-19 mild to moderate pneumonia Management with blood Ozonization in patients with Respiratory failure (CORMOR) multicentric prospective randomized clinical trial.

BACKGROUND: Following positive experience on the use of blood ozonation in SARS-CoV-2, the CORMOR randomized trial was designed to evaluate the adjuvant role of oxygen/ozone therapy in mild to moderate SARS-CoV-2 pneumonia. METHODS: The trial (ClinicalTrial.gov NCT04388514) was conducted in four different Italian centers (April-October 2020). Patients were treated according to best available standard of care (SoC) therapy, with or without O3-autohemotherapy (O3-AHT). RESULTS: A total of 92 patients were enrolled: SoC + O3-AHT (48 patients) were compared to the SoC treatment (44 patients). The two groups differed in steroids therapy administration (72.7% in SoC arm vs. 50.0% in O3-AHT arm; p = 0.044). Steroid therapy was routinely started when it was subsequently deemed as effective for the treatment of COVID-19 disease. No significant differences in mortality rates, length of hospital stay, mechanical ventilation requirement and ICU admission were observed. Clinical improvement in patients with pneumonia was assessed according to a specifically designed score (decrease in SIMEU class, improvement in radiology imaging, improvement in PaO2/FiO2, reduction in LDH and requirement of oxygen therapy ≤ 5 days). Score assessment was performed on day-3 (T3) and day-7 (TEnd) of O3-AHT treatment. A significant increase in the score was reported at TEnd, in the O3-AHT treatment arm (0 [0-1] in the SoC arm vs. 2 [1-3] the O3-AHT arm; p = 0.018). No adverse events related O3-AHT treatment was observed. CONCLUSION: In mild-to-moderate pneumonia due to SARS-CoV-2, adjuvant oxygen/ozone therapy did not show any effect on mortality, or mechanical intubation but show a clinical improvement a day 7 from randomization in a composite clinical endpoint. Larger Randomized prospective studies alone or in combination with steroids are needed to confirm our results.

Reduction of severe acute respiratory syndrome coronavirus-2 infectivity by admissible concentration of ozone gas and water.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is causing the global coronavirus disease 2019 (COVID-19) pandemic. Because complete elimination of SARS-CoV-2 appears difficult, decreasing the risk of transmission is important. Treatment with 0.1 and 0.05 ppm ozone gas for 10 and 20 hr, respectively, decreased SARS-CoV-2 infectivity by about 95%. The magnitude of the effect was dependent on humidity. Treatment with 1 and 2 mg/L ozone water for 10 s reduced SARS-CoV-2 infectivity by about 2 and 3 logs, respectively. Our results suggest that low-dose ozone, in the form of gas and water, is effective against SARS-CoV-2.

Ozone potential to fight against SAR-COV-2 pandemic: facts and research needs.

The greatest challenge the world is facing today is to win the battle against COVID-19 pandemic as soon as possible. Until a vaccine is available, personal protection, social distancing, and disinfection are the main tools against SARS-CoV-2. Although it is quite infectious, the SARS-CoV-2 virus itself is an enveloped virus that is relatively fragile because its protective fatty layer is sensitive to heat, ultraviolet radiation, and certain chemicals. However, heat and liquid treatments can damage some materials, and ultraviolet light is not efficient in shaded areas, so other disinfection alternatives are required to allow safe re-utilization of materials and spaces. As of this writing, evidences are still accumulating for the use of ozone gas as a disinfectant for sanitary materials and ambient disinfection in indoor areas. This paper reviews the most relevant results of virus disinfection by the application of gaseous ozone. The review covers disinfection treatments of both air and surfaces carried out in different volumes, which varies from small boxes and controlled chambers to larger rooms, as a base to develop future ozone protocols against COVID-19. Published papers have been critically analyzed to evaluate trends in the required ozone dosages, as a function of relative humidity (RH), contact time, and viral strains. The data have been classified depending on the disinfection objective and the volume and type of the experimental set-up. Based on these data, conservative dosages and times to inactivate the SARS-CoV-2 are estimated. In small chambers, 10-20 mg ozone/m3 over 10 to 50 min can be sufficient to significantly reduce the virus load of personal protection equipment. In large rooms, 30 to 50 mg ozone/m3 would be required for treatments of 20-30 min. Maximum antiviral activity of ozone is achieved at high humidity, while the same ozone concentrations under low RH could result inefficient. At these ozone levels, safety protocols must be strictly followed. These data can be used for reducing significantly the viral load although for assuring a safe disinfection, the effective dosages under different conditions need to be confirmed with experimental data.

Hypothesis: The electrical properties of coronavirus.

To help investigate the relationship between inflammatory and other symptoms of coronavirus and the protein-protein interactions (PPI) that occur between viral proteins and protein molecules of the host cell, I propose that the electrostatic discharge (ESD) exists including corona discharge to lead to ozone gas. I cite evidence in support of this hypothesis. I hope that the proposed will inspire new studies in finding effective treatments and vaccines for individuals with coronavirus disease in 2019. I suggest possible future studies that may lend more credibility to the proposed.