The conclusions have been made public in the scientific journal The Lancet of a study in which the effectiveness in preventing the spread of various personal protection measures, ranging from the use of masks, to maintaining interpersonal distance, and the use of protective screens, among others, have been measured.
Thus, for example, it is estimated that the chances of becoming infected if we do not maintain the interpersonal safety distance of less than one meter are 12.8%, whereas if we keep away from others by at least one meter, the chances of becoming infected drop to 2.6%.
As for the use of masks, the difference between wearing them and not wearing them makes the options of contagion go from 17.4 to 3.1 percent.

Source: https://www.thelancet.com/