Evaluation of the efficacy of chlorous acid water and sodium hypochlorite solution against SARS-CoV-2 in the presence of organic matter

Chlorous acid water and sodium hypochlorite solution are effective disinfectants against SARS-CoV-2, the virus that caused the COVID-19 pandemic. Recent studies have shown that both compounds have equivalent inactivation effects when tested on purified viruses. However, in practical applications, the presence of organic matter is common and can significantly affect disinfectant performance. We conducted several experiments comparing these two disinfectants under different conditions to better understand their practical efficacy. When an infected cell culture medium (serum-free) was used as the test virus, chlorous acid water and sodium hypochlorite solution showed reduced efficacy. This decrease was attributed to the presence of amino acids in the medium. Notably, sodium hypochlorite solution showed a more pronounced reduction in potency compared to chlorous acid water. In addition, we evaluated the SARS-CoV-2 inactivation effects of chlorous acid water and sodium hypochlorite solution under various organic loading conditions simulating real-world contamination scenarios such as blood, vomit, and saliva. The organic materials used included bovine serum albumin, sheep red blood cells, polypeptone, fetal bovine serum, and artificial saliva. The results showed that chlorous acid water demonstrated superior resistance to organic matter interference compared to sodium hypochlorite solution. These results suggest that chlorous acid water may be more effective than sodium hypochlorite solution in inactivating viruses on contaminated surfaces, particularly in healthcare settings where organic contamination is common. In summary, our research suggests that chlorous acid water may be a more effective disinfectant in practical settings.