Sunday, May 22

Covid-19. Omicron: why the FFP2 mask is (really) more effective

“The FFP2 mask can give a false sense of security”: The platform supported by the French Society for Hospital Hygiene (SF2H), titled “the FFP2 mask is not the absolute protection solution against SARS-CoV-2”, caused a stir among caregivers.

Emmenthal model

There is consensus on one point: the FFP2 mask, alone, does not make it possible to abandon all the other precautions. Faced with Sars-CoV-2, the virus responsible for Covid-19, the “Emmental model” is essential – that is to say the superposition of several precautions.

In short, “belt and suspenders” in the face of a virus whose Omicron variant is extremely contagious. The “false sense of security” feared by SF2H exists with any measure – surgical mask, vaccination, distancing, etc. It is not specific to the wearing of the FFP2 mask, which however protects better.

The SF2H also recommends “a set of measures”.

The continuation of this same sentence poses a problem for many caregivers and scientists: the SF2H indeed recommends “the wearing of a surgical mask for all staff and patients, and imposing that of an FFP2 mask during situations exposing to aerosols”.

The SF2H advocates the FFP2… in the hospital

And to remember that Sars-Cov-2 is transmitted… by the hands (hand-held transmission) and by direct airborne transmission – that is to say by the famous “large droplets”, these postillions excreted by a person in direction of another, in his presence and close to him.

Outside the hospital, physical distancing protects the eyes from droplets emitted by an infected person


In short, the signatories of the text believe that the FFP2 mask is useful for protecting its wearer in circumstances “during situations exposing to aerosols” – namely the hospital, according to them. Is it for fear of lacking such protective equipment in the performance of their duties?

An established consensus

The scientific consensus is now clear: according to all recent studies on the subject, transmission by aerosols is verified.

In July 2020, the WHO was trying to understand if, outside the medical setting, transmission by aerosols was possible even frequent. The following spring, the answer is clear: yes, especially in closed places with little or no ventilation.

Numerous scientific studies confirm this: the mode of transmission of Covid-19 occurs almost exclusively by aerosols, recalls the epidemiologist Antoine Flahault in the Revue du praticien:

We talk about aerosols but in truth it is not the virus that aerosolizes… and that’s good news because no mask would be able to filter nanoparticles! In reality, SARS-CoV-2 is inside the small droplets that we emit when we breathe. We visualize them very well when we breathe in the winter on the street

Antoine Flahault

And to add that “the emission of aerosols increases when we speak (10 times more compared to when we breathe), we sing or we shout (50 times more). These aerosols are formidable because they can remain infectious for several hours if the room is poorly ventilated, with a real risk of contamination for people who are in the same space.

The predominant aerosol infection

With the initial strains and the health measures initially in force, in 2020 and 2021 (confinements, curfew, closure of bars, restaurants, and many closed places bringing together a large public, teleworking, limitation of travel, etc.), the situations conducive to the aerosolization of the virus remained limited.

But today, especially in the middle of the winter season, the risks of contamination by aerosols are increased tenfold.

CO2 detectors, which measure the renewal (or not) of the ambient air, make it possible to know whether a place is sufficiently ventilated or not: the more the concentration of carbon dioxide increases, the greater the risk of breathing in the air already exhaled by another person… whether they are still present in the room or not.

And so, if a person was contagious, to become infected by breathing in the viral particles in suspension.

Many “conducive” situations

Therefore, the FFP2 mask appears to be a satisfactory solution in all situations likely to expose to these aerosols: transport, cinema, offices…

Karine Lacombe, head of the infectious diseases department at Saint-Antoine Hospital (AP-HP) confirms this:

The FFP2 mask has a higher filtering power than the surgical mask. It protects us, ourselves, from being affected by the people in front of us. It protects better in environments where the virus circulates a lot

Karine Lacombe

This is for example the case, she adds, “indoors, in public transport. This is the best means of protection in densely populated areas, at a time when the virus is circulating extremely intensely”, as with the outbreak of the Omicron variant.

FFP2s for teachers

In its opinion dated 8 December, the Scientific Council also recommends it, in particular to fight against Omicron, for the most fragile or exposed people – starting with the unvaccinated.

Epidemiologist Dominique Costagliola does not say anything else:

It is essential to generalize the wearing of FFP2, in particular for all caregivers, but also teachers and fragile, immunocompromised people

Dominique Costagliola

The teaching staff, in particular, ended up obtaining the distribution by the Ministry of National Education of FFP2 masks for teaching, in particular in the face of pupils with little or no vaccination and very heavily contaminated, as in kindergarten and primary.

This mask is more hermetic on the face, and has a better filtration capacity. It thus protects its wearer much better from inspired aerosols, unlike the surgical mask which essentially protects… others, by “stopping” exhaled particles.

It is more hermetic, and obviously, it has less tendency to go down below the nose

Gilles Pialoux, head of the infectious diseases department at Tenon hospital, on France 2

A risk divided by… 70!

According to a study conducted by researchers from the universities of Göttingen (Germany) and Cornell (United States), if two individuals wear a correctly positioned FFP2 mask, the maximum risk of contamination between them is only 0.4%… compared to 30% for two people wearing surgical masks. Or a risk divided by 70!

It can also be worn for up to eight hours in a row – the average length of a working day – compared to only four hours for a surgical.

Finally, it can provide better comfort, by not “sticking” to the mouth like a surgical mask.

On the other hand, it is more expensive: it is not found below 0.3 or 0.4 euro, and the strong world demand, currently, tends to pull prices up.

But given its duration of use (eight hours compared to four for a surgical device) and its good ability to be reused, even washed, it is not that expensive.

FFP2 is becoming widespread among our neighbors

In many countries, FFP2 is slowly becoming the norm, especially with the powerful Omicron wave.

In Italy, this type of mask is now compulsory, since Christmas, in all public transport, cinemas, theaters, museums and stadiums. Clearly, in all places where one is likely to be contaminated by aerosols, due to a high population density, whether indoors but also outdoors.

Same obligation in Greece in public places from this Monday, January 3.

In Austria, it is required in all closed public places, as well as in cafes and restaurants as soon as you get up or walk around. Same thing in hotels – except for the rooms. Recently, an Austrian journalist visiting France, for his report, was surprised at the low number of FFP2 masks… while contamination is exploding in our country.

In Germany, the rules vary by region: at the federal level, the rule is the obligation to wear a mask, whether FFP2 or surgical, in public transport and shops. In some Länder the FFP2 mask is imposed – sometimes even outdoors. This is the case in Bavaria or Lower Saxony, for example. This region extended this obligation to businesses last week to fight against the highly contagious Omicron variant.

In Spain, there is no obligation to wear an FFP2 mask to date, but this type of mask is tending to become widespread everywhere, including in the street.

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