Ethanol and Isopropanol Inactivation of Human Coronavirus on Hard Surfaces

Meyers, Craig; Kass, Rena; Goldenberg, David; Milici, Janice; Alam, Samina; Robison, Richard

BACKGROUND: The COVID-19 pandemic has greatly increased the frequency of disinfecting surfaces in public places causing a strain on the ability to obtain disinfectant solutions. An alternative is to supply plain alcohols (EtOH and IPA) or sodium hypochlorite (SH). AIM: There are few data showing the efficacy of multiple concentrations of EtOH, IPA, and SH on a human coronavirus (HCoV) dried on surfaces using short contact times. METHODS: Multiple concentrations of EtOH, IPA, and SH to inactivate high numbers of HCoV under real-life conditions were tested. High concentrations of infectious HCoV were dried on porcelain and ceramic tiles, then treated with multiple concentrations of the alcohols for contact times of 15 sec, 30 sec, and 1 min. Center for Disease Control (CDC) recommended three concentrations of SH were also tested. Reductions in titres were measured by using the tissue culture infectious dose 50 (TCID(50)) assay. FINDINGS: Concentrations of EtOH and IPA from 62% to 80% were very efficient at inactivating high numbers of HCoV dried on tile surfaces even with a 15 sec contact time. Concentrations of 95% dehydrated the virus, allowing infectious virus to survive. The CDC recommended 1/10 and 1/50 dilutions of SH were efficient at inactivating high numbers of HCoV dried on tile surfaces, whereas, a 1/100 dilution had substantially lower activity. CONCLUSIONS: EtOH, IPA, and SH at multiple concentrations efficiently inactivated infectious virus on hard surfaces, typical of those found in public places. Often no remaining infectious HCoV could be detected.