Alcohol-based hand disinfection and alcohols successfully inactivate SARS-CoV-2

An international team of researchers pre-published evidence which shows for the first time that two alcohol-based hand disinfectants recommended by the World Health Organization (WHO) – as well as the active ingredients ethanol and 2-propanol alone – are effective against the novel coronavirus SARS-CoV-21 . The experts are creating security for healthcare systems worldwide, because their experiments show that alcohol-based hand disinfection is an effective infection protection measure against COVID-19.

The current SARS-CoV-2 pandemic poses an enormous challenge for the global healthcare system. Effective therapeutic measures and vaccines are still lacking, so infection prevention plays a decisive role. Alcohol-based hand disinfection is an important preventive measure for healthcare professionals, and its effectiveness is essential for containing the outbreak.

Increased risk of infection: The new coronavirus spreads worldwide

According to current understanding, the virulence of the pathogen – also known as infectivity- appears to be very high. Virologists and the WHO assume that SARS-CoV-2 – after SARS-CoV and MERS-CoV – is the third highly pathogenic coronavirus that has been able to infect humans at all in the past 20 years. The result is the rapid spread of the pathogen and a high number of infected people. For this reason, many countries are making unprecedented efforts to contain the virus and interrupt transmission chains. Effective hand disinfectants must therefore also be made available quickly and be easy to access.


How effective are different hand disinfectants

For the present study, the team of scientists investigated the inactivation of SARS-CoV-2 within 30 seconds – the standard time for hygienic hand disinfection – in a suspension test. To do this, they mixed a virus suspension with varying concentrations of disinfection products or alcohols alone. The researchers then determined the amount of virus cells displaying cytopathic effects and in doing so the according reduction factors of the tested formulations or alcohol concentrations. In their experiments, the scientists examined the effectiveness of the following formulations or active ingredients:

• Formulation 1: 85 % ethanol (v/v) with 0,725 % glycerol and 0,125 % hydrogen peroxide (both v/v)
• Formulation 2: 75 % isopropanol (w/w) with 0,725 % glycerol and 0,125 % hydrogen peroxide (both v/v)
• Ethanol in different concentrations
• 2-propanol in different concentrations

Formulations 1 and 2, which are recommended by the WHO, each achieved a rapid and strong inactivation of the virus suspension. The ethanol-based formulation was highly effective from an application concentration of 40 per cent, the propanol-based formulation already achieved the maximum reduction of the viruses beginning with an application concentration of 30 per cent. For the two individually tested alcohols, ethanol and 2-propanol, a comparably high inactivation of the viruses was achieved at a 30 per cent concentration. The researchers were thus able to show that SARS-CoV-2 can be easily inactivated by the tested alcohol-based agents.

Transferability and application of the results

The authors evaluate the transferability of their results to other alcohol-based hand sanitisers as follows: “…both tested alcohols, ethanol and 2-propanol were efficient in inactivating the virus in 30 s at a minimal final concentration of at least 30 %. Alcohol constitutes the basis for many hand rubs routinely used in health care settings. Our findings are therefore of utmost importance in the current outbreak situation to minimize viral transmission and maximize virus inactivation.” These first experimental results also support the recommendation of the Robert Koch Institute (RKI) and the WHO, among others, to use to use hand disinfectants* with at least limited spectrum of virucidal activity to combat the COVID19 pandemic. According to current scientific findings, disinfectants with an efficacy against enveloped viruses (limited spectrum of virucidal efficacy) are sufficiently effective against SARS-CoV-2 within 30 seconds.

You can find the pre-publication document here.

Further Information

  1. Kratzel, A. et al: Efficient inactivation of SARS-CoV-2 by WHO-recommended hand rub formulations and alcohols. bioRxiv preprint doi , 17. März 2020

*commercial communication

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