Chlorine dioxide is a more potent antiviral agent against SARS-CoV-2 than sodium hypochlorite

Abstract

A new coronavirus (SARS-CoV-2) abruptly emerged in Wuhan, China in 2019 and rapidly spread globally to cause the COVID-19 pandemic. In this study, we examined the anti-SARS-CoV-2 activity of the potent disinfectant Cleverin, the major disinfecting component of which is chlorine dioxide (ClO ₂) and the results were compared with that of sodium hypochlorite in the presence or absence of 0.5% or 1.0% fetal bovine serum (FBS). When SARS-CoV-2 viruses were treated with 0.8 ppm ClO ₂ or sodium hypochlorite, viral titre was decreased only by 1 log TCID ₅₀/mL in 3 min. However, the viral titre was decreased by more than 4 logs TCID ₅₀/mL when treated with 80 ppm of each chemical for 10 sec regardless of presence or absence of FBS. It should be emphasized that treatment with 24 ppm of ClO ₂ inactivated more than 99.99% SARS-CoV-2 within 10 sec or 99.99% SARS-CoV-2 in 1 min in the presence of 0.5% or 1.0% FBS, respectively. In contrast, 24 ppm of sodium hypochlorite was able to inactivate only 99% or 90% SARS-CoV-2 in 3 min under similar conditions. Notably, except ClO ₂ the other components of Cleverin such as sodium chlorite, decaglycerol monolaurate and silicone showed no significant antiviral activity. Altogether, the results strongly suggest that although ClO ₂ and sodium hypochlorite are strong antiviral agents in absence of organic matters but in presence of organic matters ClO ₂ is a more potent antiviral agent against SARS-CoV-2 than sodium hypochlorite.