The World Health Organization warns against the use of face shields even though they may seem like an alternative to face masks.
Wearing a plastic visor reduces the spread of respiratory droplets that contain the virus. It reduces it, but does not prevent it. An infected person can infect, in turn, using a face shield. And the same happens with a healthy one, although on the contrary: it can be infected.
The mask is the most effective barrier to protect us from COVID-19
Using the mask we prevent the spread of the virus. That is why its use is both recommended and mandatory. Especially when, for work reasons, we are surrounded by people outside our home.
The face shield can only be partially effective at a distance of more than 2 meters, and the use of a mask would always remain mandatory
Therefore, if you use this type of face mask, we recommend that you continue to wear a mask, wash your hands, do not feel falsely protected by these face shields because their effectiveness cannot be guaranteed, and less if you are surrounded by a large number of people in a small space.
That is why we recommend always having a surgical mask on and perhaps another on hand, as a spare.
When you go out in public with people who are not at home, you should wear a mask to protect yourself and others.
If, even after all that has been explained, you decide to use one of these visors, we insist: you must wash your hands before taking it off so as not to contaminate the mask or the face.
Using the visor can be a complement to protect us from the spread of the virus, but it is not the best tool and, above all, it should not be the only one.
Health experts say the evidence is clear that masks can help prevent the spread of COVID-19, but only if people wear them at least 2 meters away from other people.
Although a face shield can protect against the droplets and sprays of infection, it may not be effective against the whole-body spray of the virus, such as a drop of blood.
2 meters might be fine for people who are asymptomatic when talking outdoors, Bourouiba says, as long as they wear a mask. The study is designed to determine whether face masks are capable of providing protection against sneezing, coughing, and airborne droplets when people are close to each other during face-to-face interaction. They found that face masks are not always enough to protect people from COVID.
These types of studies suggest that surgical masks can theoretically limit the spread of respiratory diseases, but many mask designs have not been tested in practice. It is too early to show whether masks are an effective public health measure for the population, and the data available is limited by a lack of data on whether masks are used in conjunction with other measures.
How difficult it is to enforce the rules on ffp2 masks and ensure that they are used correctly. These types of studies are still in the early stages of development and have not yet shown whether the use of surgical masks in general works as well as they suggest. For example, some nursing teams use face masks or N95 respirators when treating patients, and the use of such masks is believed to reduce the likelihood of disease transmission from an infected person.