A major Danish study has found face masks give no clear protection from Covid-19 infection to the wearer, but did not examine whether the wearer protects others by using the item. The study compared how well protected one group of people who used masks were compared with a second group who did not use them. The results of the study were announced in a statement released by In the non-face mask group, 2.1 percent of participants were infected with new coronavirus, while 1.8 percent of participants in the face mask-wearing group were infected. That difference is not big enough to...