good luck in implementing the new WHO recommendations!

At the start ofepidemic in China theWHO hardly seemed concerned with the issue of masks, which she considered " useless for healthy people and having not traveled to a risk zone " Since then, several studies have come confirm the usefulness of the mask, although most are subject to intrinsic method biases. WHO and other health organizations then made recommendations on the way to wear your mask, especially to avoid contaminations accidental. These simple tips, like that of not touching your mask once applied to the face, are in themselves already difficult to strictly observe.

In its latest update, posted on June 5, WHO saw fit to publish a comprehensive 16-page guide (in English and small print) on the use of the mask, listing an impressive number of instructions in every detail. ABSMARTHEALTH summarizes the main points for the general public.

When should you wear a mask?

If the WHO recognizes that wearing a mask – by a healthy person – is likely to prevent contamination against coronavirus, the latter is only possible " that in case of close and prolonged contact Notes the guide. Close contact is only possible when in the immediate vicinity of an infected person in a foyer or in a gathering of mass. A "non-medical" mask can be used in shops, churches and mosques, public transport, or at work " when the social distancing measures cannot be respected "And only" in areas where the virus actively circulates " France is now entirely in the green zone (with the exception of Guyana and Mayotte), one wonders who it still concerns.

What type of mask to use?

Masks for medical use should be "rectangular in shape", breathable, moisture resistant, and include three to four layers of nonwoven material (polypropylene, polyethylene or cellulose). They guarantee a filtration viruses of at least 95%. The filtration efficiency of non-medical masks, which can be made from an "infinite" number of combinations and shapes, is difficult to assess and can vary between 0.7% and 60%, indicates the WHO. A tissue will only filter 0.48% of aerosols, against 7.4% for a piece of cotton T-shirt.

Cloth masks: what type of material and how many layers?

A cloth mask should include " at least three layers " according to material selected. If you opt for cotton only, it will take at least four, and again, the filtration level will not exceed 13%. Forget very porous materials, like muslin or gauze, or elastic fabrics like elastane, which do not offer sufficient effectiveness. However, breathability must be taken into account, which is altered as the layers are multiplied. Here is the ideal combination according to the WHO:

• an inner layer of material hydrophilic (cotton or mixed cotton);
• an outer layer of the material hydrophobic (polyester or polypropylene);
• an “moderately hydrophilic” inner layer of synthetic material.

The different fabrics must also be resistant to washing at 60 ° C.

Fabric masks: which shape to choose?

The cloth masks include those with flat folds in " beak duck ". " They are designed to closely fit the nose, to the wearer's cheeks and chin ", The leaks ofair This is mainly due to a mask that is too large or poorly designed. The mask should also " be held in place comfortably, with few adjustments, using rubber bands or ties " In short, forget the masks sold in supermarkets and do almost tailor-made.

How to wash and disinfect your mask?

The mask must be changed " as soon as it is wet Recommends the WHO (which could happen in less than five minutes when it is hot and you start to sweat). Any used mask must be wrapped in plastic and put in a bag while waiting to be washed (no question of stuffing it as is in his handbag). Remember to disinfect your hands immediately afterwards. The mask must be washed " at the highest possible temperature ", with soap or detergent. Wash the mask gently " without too much friction, stretching or spinning If you use non-woven materials like polyester, says the guide. If you do not have hot water on hand, rub the mask with soap and water, and boil it for one minute flat. Another option: soak the mask in a chlorine solution diluted to 0.1% for one minute, and above all remember to rinse well afterwards, " to avoid any toxic residue "

These recommendations are certainly based on good intention. You just have to walk in the street to see the whimsical way in which some people wear the mask (on the chin, raised on the forehead, removed to cough or telephone …) and understand that its effectiveness remains entirely relative. The way in which the guide is drawn up moreover suggests that WHO is still not completely convinced of its usefulness. Such a heap of recommendations would almost end up discouraging us too.