Masks decontamination and reusability

By: Hervé FLOCH
Created: 2 April 2020 - 02:04
Updated: 2 April 2020 - 02:04

At present, all surgical and FFP2 face masks must be thrown away after a few hours of use. To offset the shortage of protective equipment, scientists, physicians and manufacturers are working together to explore ways to reuse them safely. In France, Philippe Cinquin, Professor of public health (medical data processing), a hospital practitioner, and director of the TIMC-IMAG (Techniques de l’Ingénierie Médicale et de la Complexité – Informatique, Mathématiques et Applications de Grenoble) through a recent article in "La Tribune", has provided an overview of the methods being tested by a collaborative consortium (task force) he is coordinating.

Let me share with you main aspects of their works offering promise:

In the current Covid-19 epidemic situation, to potentially help solving the critical mask shortage in hospitals and throughout the entire chain of care (which fortunately is not yet the case), it is wondered whether it would be possible to define a protocol for recycling used and contamined masks. The aim is of course to eliminate the viral load after the first use while guaranteeing the same performance level as a new mask. This day, as part of an interdisciplinary consortium formed by the French National Center for Scientific Research (CNRS) and the French Alternative Energies and Atomic Energy Commission (CEA) and comprising physicians, scientists and manufacturers, Philippe Cinquin's collaborative team is exploring the comparative advantages of washing with a detergent at 60 or 95°C, autoclaving at 121°C for 50 minutes, gamma or beta radiation, exposure to ethylene oxide, and heating at 70°C in dry heat or in water. For surgical masks, these works were able to show that they maintain their performance level after washing at temperatures up to 95°C. Good results have been also obtained with autoclaving and gamma radiation. To be precise, It has been noted a less than 2% loss in filtration efficiency, which means that the best quality masks, used and treated, perform better in the tests than unused ones of lesser quality. Hydrogen peroxide gas (maybe with UV-light assistance) and oxygen plasma as other possible disinfection agents to be considered further.

Concerning FFP2 respirators, the first results obtained by the Apave agency in Grenoble (France) has shown that ethylene oxide treatment does not hinder performance, while gamma radiation apparently does. Lastly, the International Centre for Infectiology Research ( CNRS / Inserm / ENS Lyon / Université Claude Bernard Lyon 1)  has demonstrated that dry heat at 70°C is very effective for destroying a calibrated viral load deposited on surgical and FFP2 masks.

Next step according to Philippe Cinquin communication, they will be testing the combination of washing and other disinfection methods. New test beds, at the Reaction and Process Engineering Laboratory (CNRS / Université de Lorraine) in Nancy and the CEA-Grenoble, will be used to test the performance of surgical masks, and our CIC-IT colleagues at the Nancy University Hospital Centre will explore ways of increasing the capacity to collect used masks. Moreover, Philippe Cinquin's collaborative team just joined "ReUse", an international task force that is working on exactly the same topics, and they are going to share all of their results.

I am currently trying to be touch with Philippe Cinquin to possibly have him participating to that e-forum bringing recent advances on their promising works and also through discussions and sharing of information facilitated by the European Cluster Alliance (ECA) with the support of the European Commission taking place on a daily basis.

Looking forward to hear from you regarding that alternative to fight the Covid-19 crisis and the shortage of masks!