A Pseudoscience Tale: Insufficient Evidence Regarding Chlorine Dioxide’s Toxicity and Efficacy

Abstract

Background. Chlorine dioxide (ClO2) and its related compounds have been proposed as a treatment for several diseases; their popularity increased during the COVID-19 pandemic. This study aimed to identify, characterize, and synthesize the existing publications regarding ClO2 and its related compounds' toxicity and efficacy as a treatment. Material and Methods. A scoping systematic review of animal and human studies was carried out in PubMed and EMBASE from their origin to October 20, 2020. Outcomes of interest were toxicity and efficacy of ClO2 and related compounds. After title, abstract, and full-text peered-review screening, data was extracted and synthesized. Methodological and reporting bias was analyzed in order to identify low-quality studies. Results. We identified 15 animal and 19 human studies out of 752 articles found in academic literature. The latter selection included 13 toxicity case reports and 6 clinical studies reporting on the topical and systemic administration of ClO2. Animal studies hinted at the possibility of reproductive, developmental, thyroid, hematological, and nephrotic damage in different species. Most studies displayed methodological bias and low quality in reporting. On the human side, several case reports described mild and severe intoxications with ClO2 and related compounds at different doses in healthy and comorbid individuals. Clinical studies revealed no conclusive evidence on ClO2 as an effective systemic treatment. Conclusions.The principle of precaution should be called upon until quality evidence is provided; new and more comprehensive pre-clinical studies are needed before carrying out human trials. Meanwhile, tighter regulations on this substance could prevent adverse toxicological events.