Comparison of the SARS-CoV-2-inactivating activities of the differently manufactured hypochlorous acid water products with various pH

Abstract

The use of effective disinfectants is a key method of controlling the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Hypochlorous acid water (HAW) has a broad spectrum of virucidal activities. We previously reported that acidic electrolyzed water, one of the HAW products, had potent SARS-CoV-2-inactivating activity and showed promise as a disinfectant. However, different manufacturing methods have produced several HAW products with various pH values. Here, we compared the SARS-CoV-2-inactivating activities of various HAW products. At sufficiently high volume and residual chlorine concentration (RCC), the HAW products inactivated SARS-CoV-2 efficiently regardless of pH or manufacturing method. However, although HAW products at pH 5.0–6.4 maintained high RCC and sustained virucidal activity for 21 days, the RCC rapidly decreased in HAW products at pH ≤ 3.0. Our results may guide in choosing appropriate HAW products for different usage situations. HIGHLIGHTS Hypochlorous acid water (HAW) showed virucidal activity against SARS-CoV-2.; Various HAW products showed virucidal activity regardless of manufacturing methods.; Virucidal activity of HAWs depends on the amount of residual chlorine (RC).; HAWs with pH 5.0–6.4 maintained high RC concentration for 21 days.; RC concentration was rapidly decreased in HAW with pH ≤ 3.0.;

Keywords

• disinfectant
• hypochlorous acid water
• manufacturing method
• ph
• sars-cov-2