In-vivo efficacy of alcohol-based hand rubs against noroviruses: a novel standardized European test method simulating practical conditions

Abstract

Non-enveloped viruses are particularly resistant to disinfectants, so it is necessary to use disinfectants with proven virucidal activity in order to prevent and control the spread of viral infections. However, a test such as EN 1500, which uses an internal standard as the reference treatment for determining the bactericidal efficacy of hand rubs, is still lacking. This study aimed to establish a European standard for testing the in-vivo efficacy of hand rubs against non-enveloped viruses. The concentration and mode of application of ethanol as the reference were determined, and compared with the efficacies of two commonly used hand rubs. The hands of volunteers were contaminated with murine norovirus strain S99. 70% wt/wt ethanol (2 x 3mL in 2 x 30s) was used as the internal reference treatment. The commercial ethanol-based hand rub was able to reduce the titre of murine norovirus significantly in 30s, whereas a hand rub based on ethanol and propan-2-ol was significantly less effective compared with the reference. This study established a possible standard for testing the in-vivo efficacy of hand rubs against non-enveloped viruses using murine norovirus, a low contamination volume technique and ethanol as the internal reference. These findings need to be confirmed in European ring trials.