ABSTRACT
Atmospheric ozone is produced when nitrogen oxides react with volatile organic compounds. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genome contains a unique N-terminal fragment in the Spike protein, which allows it to bind to air pollutants in the environment. 'Our approach in this review is to study ozone and its effect on the SARS-CoV-2 virus and patients with coronavirus disease 2019 (COVID-19). Article data were collected from PubMed, Scopus, and Google Scholar databases. Ozone therapy has antiviral properties, improves blood flow, facilitates the transfer of oxygen in hypoxemic tissues, and reduces blood coagulation phenomena in COVID-19 patients. Ozone has immunomodulatory effects by modulating cytokines (reduction of interleukin-1, interleukin-6, tumor necrosis factor-α, and interleukin-10), induction of interferon-γ, anti-inflammatory properties by modulating NOD-, LRR- and pyrin domain-containing protein 3, inhibition of cytokine storm (blocking nuclear factor-κB and stimulating nuclear factor erythroid 2-related factor 2 pathway), stimulates cellular/humoral immunity/phagocytic function and blocks angiotensin-converting enzyme 2. In direct oxygen-ozone injection, oxygen reacts with several biological molecules such as thiol groups in albumin to form ozonoids. Intravenous injection of ozonated saline significantly increases the length of time a person can remain hypoxic. The rectal ozone protocol is rectal ozone insufflation, resulting in clinical improvement in oxygen saturation and biochemical improvement (fibrinogen, D-dimer, urea, ferritin, LDH, interleukin-6, and C-reactive protein). In general, many studies have shown the positive effect of ozone therapy as a complementary therapy in the recovery of COVID-19 patients. All the findings indicate that systemic ozone therapy is nontoxic and has no side effects in these patients.