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

Hatanaka, Noritoshi; Xu, Bingting; Yasugi, Mayo; Morino, Hirofumi; Tagishi, Hideaki; Miura, Takanori; Shibata, Takashi; Yamasaki, Shinji

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.