Hypochlorous acid solution is a potent antiviral agent against SARS-CoV-2.

Hatanaka, Noritoshi; Yasugi, Mayo; Sato, Tomoko; Mukamoto, Masafumi; Yamasaki, Shinji

AIM A novel coronavirus, termed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) suddenly appeared in Wuhan, China and has caused pandemic. In this study, we evaluated antiviral activity of purified hypochlorous acid (HClO) solution against coronaviruses such as SARS-CoV-2 and transmissible gastroenteritis virus (TGEV) responsible for pig diseases. MATERIALS AND RESULTS In a suspension test, 28.1 ppm HClO solution inactivated SARS-CoV-2 in phosphate buffered saline (PBS) with the reduction of 104 of 50% tissue culture infectious dose/mL (TCID50 /mL) within 10 sec. When its concentration increased to 59.4 ppm, the virus titer decreased to below the detection limit (reduction of 5 logs TCID50 ) within 10 sec even in the presence of 0.1% fetal bovine serum (FBS). In a carrier test, incubation with 125 ppm HClO solution for 10 min or 250 ppm for 5 min inactivated SARS-CoV-2 by more than 4 logs TCID50 /mL or below the detection limit. Since the titer of TGEV was 10 fold higher, TGEV was used for SARS-CoV-2 in a suspension test. As expected, 56.3 ppm HClO solution inactivated TGEV by 6 logs TCID50 within 30 sec. CONCLUSIONS In a carrier test 125 ppm HClO solution for 10 min incubation is adequate to inactivate 4 logs TCID50 /mL of SARS-CoV-2 or more while in a suspension test 56.3 ppm HClO is adequate to inactivate 5 logs TCID50 /mL of SARS-CoV-2 when incubated for only 10 sec regardless of presence or absence of organic matter. SIGNIFICANCE AND IMPACT OF STUDY Effectiveness of HClO solution against SARS-CoV-2 was demonstrated by both suspension and carrier tests. HClO solution inactivated SARS-CoV-2 by 5 logs TCID50 within 10 sec. HClO solution has several advantages such as none toxicity, none irritation to skin and none flammable. Thus, HClO solution can be used as a disinfectant for SARS-CoV-2.