Inactivation of Severe Acute Respiratory Syndrome Coronavirus 2 by WHO-Recommended Hand Rub Formulations and Alcohols

Abstract

Infection control instructions call for use of alcohol-based hand rub solutions to inactivate severe acute respiratory syndrome coronavirus 2. We determined the virucidal activity of World Health Organization-recommended hand rub formulations, at full strength and multiple dilutions, and of the active ingredients. All disinfectants demonstrated efficient virus inactivation.

Keywords: 2-propanol; 2019 novel coronavirus disease; COVID-19; SARS; SARS-CoV-2; World Health Organization; coronavirus; coronavirus disease; ethanol; hand sanitizer; respiratory infections; severe acute respiratory syndrome coronavirus 2; viruses; zoonoses.

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Formula

Figure 1

Virucidal activity of original and modified World Health Organization (WHO)–recommended hand rub formulations I and II for inactivating severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The means of 3 independent experiments with SDs (error bars) and percentage of inactivation at different concentrations are shown. A) WHO original formulation I; B) WHO original formulation II; C) WHO modified formulation I; D) WHO modified formulation II. Insets in panels C and D show regression analyses of the inactivation of coronaviruses. Dark gray bar shows cytotoxic effects, calculated analogous to virus infectivity. Reduction factors are included above the bar. Dilutions of the WHO formulations ranged from 0–80% with an exposure time of 30 s. Viral titers are displayed as TCID₅₀/mL values. BCoV, bovine coronavirus; LLOQ, lower limit of quantification; MERS-CoV, Middle East respiratory syndrome coronavirus; SARS-CoV, severe acute respiratory syndrome coronavirus; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2; TCID₅₀/mL, 50% tissue culture infectious dose.

Figure 2

Effect of commercially available alcohols in inactivating SARS-CoV-2. The means of 3 independent experiments with SDs (error bars) are shown. A) Results for ethanol. B) Results for 2-propanol. Dark gray bar indicates cytotoxic effects, calculated analogous to virus infectivity. Reduction factors are included above the bar. The biocide concentrations ranged from 0–80% with an exposure time of 30 s. Viral titers are displayed as TCID₅₀/mL values. LLOQ, lower limit of quantification; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2; TCID₅₀/mL, 50% tissue culture infectious dose.