Comparative evaluation of chlorous acid and sodium hypochlorite activity against SARS-CoV-2

A novel coronavirus, named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), suddenly emerged in China in 2019, spread globally and caused the present COVID-19 pandemic. Therefore, to mitigate SARS-CoV-2 infection effective measures are essential. Chlorous acid (HClO(2)) has been shown to be an effective antimicrobial agent. However, at present there is no experimental evidence showing that HClO(2) can inactivate SARS-CoV-2. Therefore, in this study, we examined the potential of HClO(2) to inactivate SARS-CoV-2 in presence or absence of organic matter and the results were compared with that of sodium hypochlorite (NaClO), another potent antimicrobial agent. When concentrated SARS-CoV-2 was incubated with 10 ppm HClO(2) for 10 s, viral titre was decreased by 5 log of 50% tissue culture infective dose per mL (TCID(50) ml(−1)). However, the same concentration of NaClO could not inactivate SARS-CoV-2 as effectively as HClO(2) did even after incubation for 3 min. Furthermore, 10 ppm HClO(2) also inactivated more than 4.0 log of TCID(50) within 10 s in the presence of 5 % fetal bovine serum used as mixed organic matters. Our results obtained with HClO(2) are more effective against SARS-CoV-2 as compared to NaClO that can be used for disinfectant against SARS-CoV-2 .