Recent studies have shown that multi-layer cloth masks can provide enough filtration for personal protection and block virus particles exhaled by others, reducing transmission of the virus by more than 70% in some cases. Until a vaccine arrives, then, both disposable and reusable masks remain an important tool for protection against the SARS-CoV-2 virus.
The scientific community strongly supports the use of masks: recent studies have confirmed that they reduce the chances of transmitting and catching the coronavirus and, where transmission does occur, they reduce the severity of the infection in people who become ill.
Wearing a mask, therefore, means fewer people fall ill, and the viral load of SARS-CoV-2 drops by 30%.
But which masks are the most effective, and how should they be used?
There are three categories of mask on the market:
1. medical devices (MD)
2. personal protective equipment (PPE)
3. reusable (or community) masks
Surgical masks, normally worn by doctors and healthcare workers, are classed as medical devices. Think of a dentist extracting a tooth: a person wearing a surgical mask not only avoids contaminating the operating field but also protects themselves from any splashes of fluid that might reach their mouth. Their filtering capacity towards the wearer is low (estimated at around 20%), while their filtering capacity outwards is extremely high and, in the case of bacteria, can exceed 95%.
Their key characteristics are:
- resistance to liquid splashes
- breathability
- efficiency in filtering out incoming bacteria
- freedom from microbes
Surgical masks, however, are disposable and deteriorate over time. The fabric they are made from contains synthetic fibres, so if they are not disposed of properly they seriously pollute the environment.
Next come personal protective equipment (PPE) masks, classified according to their filtering capacity:
1. FFP1, which filters at least 80% of the small particles in the air and is therefore not very effective at protecting against pathogens
2. FFP2, which filters at least 94% of the particles in the air
3. FFP3, which filters at least 99% of the particles in the air and is therefore used in settings with a high risk of infection
Personal protective equipment protects the wearer from what circulates in the surrounding environment, especially substances in aerosol form (that is, very small droplets).
PPE masks can come with or without a valve: those with a valve are certainly more comfortable because they make breathing out easier. But be careful: if the person wearing a valved mask is positive for COVID-19, the aerosol they breathe out, which contains viral particles, will be released into the environment, so this type of protection will not stop the infection from spreading. This is why these masks are described as “selfish”.
Finally, there are reusable masks. They belong neither to the medical device group nor to the PPE group; recent studies, however, have shown that multi-layer cloth masks can provide enough filtration for personal protection and block virus particles exhaled by others, reducing transmission of the virus by more than 70% in some cases.
Which fabrics are most suitable? In fact, many fabrics can filter larger droplets while being ineffective against smaller droplets, or aerosols. Natural fibres perform better than synthetic ones, and two layers are certainly better than one. Besides the materials, protection also depends on how well the mask fits and seals against the face. The important thing, though, is knowing how to clean them: before being reused, this type of mask must be washed thoroughly at high temperatures (at least 60 degrees).
How do you wear a mask correctly?
Using a mask incorrectly can cancel out its benefits completely and even make it dangerous. That is why it is worth following a few important steps to put it on properly, just as a surgeon does before an operation.
1. Before touching the mask, wash your hands thoroughly with warm water and soap or with an alcohol-based gel.
2. Place the mask on your face, carefully covering your nose and mouth. Surgical masks and PPE masks have a metal strip along the top edge: pressing it with your fingers shapes the strip to your nose so that the mask fits snugly. The lower edge, on the other hand, should go under your chin and fit closely.
3. Once the mask is on, avoid touching it, because doing so risks contaminating your hands. If you have to touch it, it is advisable to wash your hands afterwards as well.
4. When you have finished using it, remove the mask by touching only the elastic loops, never the front.
5. Throw a disposable mask into a bin that is then closed immediately. Reusable or community masks should be washed at high temperatures (60°).
Does wearing a mask really help?
The data available today indicate that masks can help reduce the risk of the disease spreading. Other evidence has shown that wearing a mask reduces the amount of virus that can be transmitted to the wearer, leading to milder or asymptomatic infections. Finally, an American study recently published in Nature suggests another possible benefit of mask use: if more people who test positive for COVID-19 have mild symptoms, this could help build population-level immunity without increasing the risk of serious illness and death.
It is worth remembering that wearing a mask alone is not enough to limit the spread of COVID-19: it is essential to follow the other rules as well, namely physical distancing, thorough hand washing and ventilating the rooms you spend time in.
Source: Scientific Brief: Community Use of Cloth Masks to Control the Spread of SARS-CoV-2
Credits: Photo by Flavio Gasperini on Unsplash
