Sufficiently high concentrations of active ingredients for reliable efficacy of hand disinfectants

Ethanol, along with 2-propanol and 1-propanol, is a commonly used active ingredient in alcohol-based hand disinfectants. The ethanol content of a product is indicated either in mass percent % (w/w) or in volume percent % (v/v). Further information can be found here.

What influence does the alcohol content have?

The level of alcohol content has a direct effect on several properties of the hand disinfectant, especially on its efficacy. Basically, it can be said that a product with a higher alcohol content has the following properties compared to a product with a lower alcohol content [1,2]:

• better efficacy (with otherwise the same application)
• shorter application time (for the same efficacy)
• smaller application volume required (for the same efficacy)
• shorter drying time of the hands (for the same volume)

At what active ingredient content is a product effective?

e proof of efficacy of a product must be provided by the product formulation. A statement on efficacy cannot be made in general terms based on the active ingredient content. However, based on the literature, an estimation is possible for the active ingredient ethanol as an example: at a very low ethanol content of less than 70 % (v/v), sufficient efficacy cannot be assumed [3]. In contrast, users of products with ethanol concentrations of 80 % (w/w) and more (but not pure ethanol) are on the safe side [4,5].

The effectiveness of products for hygienic hand disinfection is proven by testing according to the valid version of EN 1500. This information can be found on the label of the products.

Ensure patient protection through the use of high-ethanol products

For products for hygienic hand disinfection in the medical sector, efficacy according to EN 1500 is mandatory. Highly alcoholic products meet the requirements when using a volume of 3 ml in a contact time of 30 s. Products with a lower ethanol content often require a larger application volume or a longer exposure time to pass the test.

It should be noted, however, that when performing hand disinfection in practice, the exposure time specified by the manufacturer is often not adhered to and often less volume than recommended is used [6]. Under these conditions, sufficient efficacy, especially of products with a very low active ingredient content, is questionable. Since a low ethanol content also leads to a longer drying time of the hands, it can be assumed that even lower volumes are used or that hand hygiene is neglected altogether. Therefore, in the interest of patient protection, high-ethanol products should preferably be used.

Due to the proven superior efficacy and the associated patient protection, it is advised to use products with a high alcohol content (for ethanol of at least 80 %).

For more information or our conversion calculator, please contact our Expert Team.

Sources:

1. Price L et al. (2022) Systematic review on factors influencing the effectiveness of alcohol‑based hand rubbing in healthcare. Antimicrob Resist Infect Control. 24;11(1):16.
2. Macinga DR et al. (2014) The relative influences of product volume, delivery format and alcohol concentration on dry-time and efficacy of alcohol-based hand rubs. BMC Infect Dis. 14(1):511.
3. Kramer A et al. (2002) Limited efficacy of alcohol-based hand gels. The Lancet 359:1489-1490.
4. Suchomel M et al. (2012) Testing of the World Health Organization recommended formulations in their application as hygienic hand rubs and proposals for increased efficacy. Am J Infect Control 40:328-331.
5. Kampf G et al. (2002) Spectrum of antimicrobial activity and user acceptability of the hand disinfectant agent Sterillium Gel. Journal of Hospital Infection 52(2):141-147.
6. Schulz-Stübner S et al. (2019): Practice and attitudes toward alcohol-based hand disinfection among German infection control teams. Infect Control Hosp Epidemiol. 40(5):609-612.