Recent case studies on the use of ozone to combat coronavirus: Problems and perspectives

Background

The COVID-19 pandemic, caused by the SARS-CoV-2 coronavirus, prompted an urgent search for treatments and disinfection methods beyond drug-based therapy. Ozone (O3) had already been used for decades in water treatment, disinfection, and complementary medicine, and earlier laboratory work had shown that ozone can inactivate a range of viruses, including other coronaviruses and RNA viruses. Researchers from BMS College of Engineering in Bengaluru, India, set out to gather and evaluate the published case studies and evidence on using ozone against coronaviruses, and to consider what gaps remained before it could be more widely adopted.

Study design

This was a narrative literature review, not a new laboratory experiment or clinical trial. The authors searched and compiled existing published case studies, in vitro findings, and reports on ozone's antiviral action, along with the proposed chemical mechanisms by which ozone breaks down molecules and disrupts viral structures. They examined how ozone has previously been used for surface disinfection, air treatment, and as a complementary therapy in a small number of clinical case reports, then compared these findings against what was known about SARS-CoV-2's structure and susceptibility to oxidising agents.

Findings

The review reported that ozone, being an unstable molecule, breaks down into reactive oxygen species and ozonides, creating an environment that is toxic to viral particles, including RNA viruses similar to SARS-CoV-2. Case studies and prior research cited in the paper suggested ozone could damage the lipid envelope and proteins of coronaviruses, reducing their ability to infect cells, and that ozone-based disinfection had shown effectiveness on surfaces and in air. However, the authors were clear that the clinical evidence specifically for ozone therapy as a treatment for COVID-19 in humans remained limited, based on isolated case reports rather than controlled trials, and that dosing, delivery method, and safety parameters were not yet standardised.

What the authors concluded

The authors concluded that ozone shows biological plausibility and promise as a complementary tool against coronaviruses, both for environmental disinfection and as a possible adjunct therapy, based on its known oxidative antiviral mechanism. They stated that further clinical studies with proper external validity were needed to confirm effectiveness, establish safe and consistent dosing protocols, and move the existing case-study evidence toward more rigorous trial-based confirmation before ozone could be recommended as a standard treatment approach.

Limitations of this study

As a narrative review of existing case studies rather than original experimental or clinical research, this paper's conclusions are only as strong as the studies it draws on, most of which were small, uncontrolled case reports rather than randomised trials. There was no new primary data generated, no standardised ozone dosing or delivery protocol assessed, and no long-term safety or efficacy data for ozone therapy specifically in COVID-19 patients. The authors themselves highlighted the need for further clinical validation, and readers should treat the findings as an early, exploratory synthesis of the evidence available at the time rather than a definitive verdict on ozone's effectiveness against coronavirus.