For instance, a mask with just 50 percent efficacy in reducing droplet transmission worn by just 50 percent of people can reduce the Re from 2.4 to about 1.35—roughly the level of seasonal influenza. This means that, if there were one hundred cases of such an infection at the beginning of the month, in a no-mask scenario, there would be 31,280 cases at the end of the month; but in a mask scenario, there would be only 584.
