Despite the presence of advertisements and signs reminding you of the obligation to wear a mask on public transport and in many places indoors, it can sometimes happen that you run into someone who does not use it or who does not wear it, covering their nose and mouth properly. In cases like this one often wonders if one can consider oneself equally protected by one’s own mask, or if the lack of attention of others can pose some more risk for oneself and the spread of the coronavirus.
Generally speaking, masks work at their best in terms of protection against contagion when everyone is wearing them. As we have learned in over a year and a half of the pandemic, their main function is to block the viral particles emitted by those who are unknowingly contagious.
The masks also offer protection to everyone else, making it less likely that any viral particles circulating in the air will be inhaled, the first step towards contagion. In well-ventilated places the risks are further lower than in those where there is not sufficient ventilation.
However, several studies have collected convincing evidence that masks can offer good protection to the wearer, even if there are people around who do not use them and who could be contagious. The pandemic has offered researchers the opportunity to deepen the knowledge they already had on the spread of some viruses through the air, even if finding clear and clear answers is very difficult because the risks of contagion vary according to the environments studied, the types of masks worn, the behaviors of individuals and the factors that make some individuals more exposed to viral infection than others (we are all different, even from a medical point of view, after all).
The New York Times has recently put together a collection of studies and research on the level of protection offered by masks to the wearer, even when indoors with others who do not use or wear them incorrectly. With different results, due to the variables we mentioned earlier, all studies show a reduction in risk.
Researchers from the United States Centers for Disease Control and Prevention (CDC) have experienced various conditions in which a contagious person, without a mask, coughs in the direction of another person with a surgical mask about two meters away, in an indoor environment.
They calculated that the surgical mask protects from 7.5 percent of the viral particles produced in the simulation, but that you can get to about 65 percent by having the foresight to tie the cords, so that it is more adherent to the face. In the case of using an additional layer of cloth over the surgical mask, an 83 percent reduction in the risk of exposure was achieved.
Another study carried out at Virginia Tech (United States), circulated between late winter and early spring, instead took into consideration the protection offered by different types of masks. Most have been shown to be useful in blocking larger saliva droplets, such as those emitted during a sneeze, which could contain large amounts of viral particles if produced by an infectious person. For the smallest particles that can remain in suspension for a long time (aerosol) the level of protection was found to be lower, with greater protection in the event that more layers of fabric are used and a filter to protect the nose and mouth.
For a research conducted in Tokyo (Japan), the protection from the coronavirus offered by different types of masks for the wearer was investigated. The researchers found that even the simplest cotton models offer a level of protection between 17 and 27 percent. However, the best results in terms of protection have been achieved with surgical masks and with FFP2 type masks, especially if they adhere very well to the face.
The protection levels of the masks had already been studied in the past, albeit with less attention and interest from the public and institutions. A research conducted in 2008 had tested them on real volunteers, rather than on dummies as is often the case for this type of research (to reduce variables and for safety reasons). The study reported a reduction in respiratory virus exposure of up to 60 percent with tissue masks, up to 76 percent with surgical masks, and up to 99 percent with FFP2.
In general, most laboratory studies point to FFP2s as the best protection system for the wearer, even in circumstances where you are sharing indoor environments with people who are not using the masks. Their use is especially recommended in circumstances where physical distance cannot be maintained, in crowded places and in those where there is no adequate air exchange.
However, the research is still ongoing and it is good to remember that there can be marked differences between the simulated experiences in the laboratory and those in real life, where there are a much higher number of variables.
Vaccination against the coronavirus continues to be the most suitable solution to reduce the risks of falling ill with COVID-19, especially in its most serious forms. The vaccine protects against the disease, but does not completely exclude infections and for this reason it is important to continue to use the masks indoors by wearing them correctly, covering both the nose and the mouth. The more people wear them, the lower the risks for everyone. Just like with the vaccine, it is a gesture of concern towards others and towards oneself.