Are medical masks reusable? Yes, but under conditions.

Although the recommendations of the health authorities are very clear concerning the impossibility of reuse of medical masks, with the accumulation of waste and the cost borne by citizens, voices are calling for reuse under certain conditions.

The World Health Organization stresses that “medical masks are used only once” and calls for “the immediate elimination of used masks”.

However, in the event of a severe shortage of stocks, similar to what happened in the early stages of the pandemic, the organization approves exceptional procedures based on disinfecting used masks for reuse.

And the United States Emergency Medication Agency previously authorized the disinfection of N95 (N95) masks (for medical personnel, and the equivalent of FFP2 masks) by spraying them with hydrogen peroxide.

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How to disinfect a muzzle

There are other methods of disinfection by exposing the masks to high temperatures or using ultraviolet rays.

But Dr Donny Courbet, specialist in microbiology and expert in hygiene and member of the “Adios Corona” association, which brings together French scientists from various specialties, underlines that “this material (disinfection) is not practical for individuals” .

However, to reduce the plastic pollutants resulting from polypropylene masks and the cost borne by families, Adios Corona calls for the use of “envelope technology” to disinfect masks used in the family environment, because the risks of exposure to viruses are much lower compared to medical staff.

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7 days

The technology consists of placing the used muzzle, provided it is not damaged, in a paper envelope and writing down the date, and leaving it for a period of 7 days.

Doctor Courbet declares: “Several practical studies show that the viruses (SARS-Cove-2) present on a muzzle almost all die in 7 days”.

A study prepared by the University of “Hong Kong”, published in the magazine “The Lancet”, also showed that after a week, the percentage of viruses detectable outside the muzzle is limited to 0, Only 1%.

Peter Tsai, the inventor of the electrostatic charge (static electricity) technology used in “N95” masks, which relies on the attraction of particles to prevent their entry, confirms the effectiveness of “shell technology”.

“In order to reduce consumption and protect the environment, I recommend that the general population reuse the muzzle after 7 days, between 5 and 10 times. Like I do, ”Tsai told AFP.

The retired expert, who returned to his job at the University of “Tennessee” after the Covid-19 crisis, says the muzzle can be placed in the oven and exposed to sufficient heat to kill the virus without burning plastics, explaining: “The temperature should be between 70 and 75 degrees Celsius.”

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‘More like underwear’

But Tsai recommends not washing the masks, saying that “washing without lye can’t wash off the virus.” Washing with detergent will damage the (electrostatic) charge ”.

But he considers that in the latter case, despite the drop in purification capacity, a washed muzzle may still be more effective than a fabric muzzle.

That’s the conclusion of tests conducted by the French consumer protection group OFC-Co-Schwazer, the results of which were published this week.

Test results showed that the repeated washing process of 3 masks with 95% purification capacities for 3 micron particles in the washing machine at a temperature of 60 ° C and placing them in the washing machine and then dry under iron, ten times, in most cases losing only five percent of their purification capacity.

This week, the French group confirmed that “despite a slight flocculation, bleached medical masks are equivalent in terms of protective capacity to the best fabric masks, and can exceed them”.

Tests carried out by Philippe Froman, researcher at the French College of Textile Engineering of Roubaix, Annecy, on 3 types of masks, produced similar results.

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Can the masks be washed?

His study showed that after washing them at least 5 times, “there is hardly any difference (in the purification) of the 3 micron particles, the difference appears in the purification of smaller particles”, according to preliminary results that have not yet been published, according to the researcher.

He considers that these masks “remain in an ideal position to play their role of protecting the population in general”, referring to the standards applied in France for fabric masks, which have a filtering capacity of no more than 90% of particles with a size of 3 microns.

The researcher explains: “I would rather change the muzzle every 4 hours and wash it, rather than wearing it for consecutive days like some do. It’s a bit like underwear.”

But until the test results are published in scientific references, the health recommendations will remain the same.

This week, the French public health directorate stressed the need to “throw medical masks after their use in the trash”, stressing that the question of the reuse of masks is currently “under study” in France.

But the head of the Department of Biomedical Engineering at Binghamton University, USA Kiming Yee said, “I don’t think (medical masks) are washable.”

Yi, who is working on setting standards for ultraviolet disinfection to protect the ozone layer, told AFP it may be possible to “reuse” medical masks, but “further studies are needed “.