Since the start of the COVID-19 pandemic and the recommendation to adopt barrier gestures, the use of alcohol-based gels and solutions to disinfect hands has become part of our daily routine, whenever washing with soap and water is not possible. Is a product still effective if it has been kept for several months in a handbag or in a dispenser with a dosing pump at the entrance to a building? ANSES has just published an opinion on this issue.
Does the alcohol content of these gels remain stable over time?
The virucidal effectiveness of hand sanitiser gels and solutions is based on their alcohol concentration. However, there is a risk that the alcohol will evaporate over time. The Agency tested hand sanitiser products manufactured according to the formulas laid down by the Ministerial Order of 13 March 2020 with several representative storage and use scenarios:
- a pocket bottle (100 mL) for personal use: used once a week for 5 months;
- a 500 mL bottle with a dosing pump for moderate use: used every two hours for 8 to 10 hours, over 3 weeks;
- a 1 L bottle with a dosing pump, for example in a shop entrance: used intensively, every 5 minutes for 8 to 10 hours, over 3 days;
- a 5 L refill bottle, opened daily for 15 minutes to transfer 200 mL to a smaller container, for 5 weeks.
The result: only products in bottles with a dosing pump used moderately had a 5-10% reduction in their alcohol content over three weeks. "Pumps are less airtight than caps, so the alcohol evaporates more easily," explains Catherine Gourlay-Francé, Deputy Director of Regulated Products Assessment at ANSES. To ensure that the products you use are effective, you should choose the type of container that is best suited to the frequency of use, reserving pump-action bottles for frequent use.
More than 99.99% of coronaviruses eliminated
It is important to choose your hand sanitiser carefully, as not all of these products are specifically designed to be effective against coronaviruses over time. To compensate for any possible reduction in alcohol content over time, ANSES recommends using hand sanitiser products with an alcohol concentration (ethanol or isopropanol) of at least 65%.
Tests conducted on hand sanitiser products, manufactured to combat the pandemic according to the formulas described in the Ministerial Order of 13 March 2020, have shown that products whose labels state that they have an alcohol content of at least 65% eliminate more than 99.99% of enveloped viruses, including coronaviruses.
Gels and solutions claiming "virucidal activity in accordance with standard EN 14476", or "alcohol-based solution recommended by the World Health Organization for hand antisepsis" or "alcohol-based gel for hand antisepsis - exemption order" are recognised to be effective against coronaviruses.
Recommendations for storing hand sanitiser gel
To ensure the effectiveness of hand sanitiser products, you are advised to:
- comply with the storage and use instructions given on the packaging;
- store the product in a clean place away from heat and sunlight;
- close the container securely after use;
- if the bottle is fitted with a dosing pump, use the product fairly quickly after opening;
- when transferring the product from one container to another, do this in a place with a temperature below 20°C to limit evaporation of the alcohol;
- if reusing a container, clean it before refilling it, at least with soap and water, and limit the number of times it is reused.
A two-stage response to the pandemic
"To make them available more quickly in the context of the pandemic, it was decided that hand sanitiser gels complying with strictly defined formulas could be placed on the market under an exemption," says Catherine Gourlay-Francé. ANSES had been asked to determine the effectiveness criteria for these products, whose use is recommended as part of the barrier gestures against SARS-CoV-2 transmission.
In a first opinion (PDF) published in June 2020, the Agency had already issued recommendations based on the available knowledge on enveloped viruses, the group to which coronaviruses belong. The supplementary opinion published in June 2021 confirms and clarifies these recommendations, mainly by providing data on the effectiveness of these products specifically against coronaviruses and under real conditions of use.