Time to upgrade from cloth and surgical masks to respirators?

Your questions answered on masking up, write Leyla Asadi, University of Alberta; C Raina MacIntyre, UNSW; Lisa M Brosseau, University of Minnesota, and Trish Greenhalgh, University of Oxford With the rapid spread of Omicron, many countries are rethinking their COVID mask advice for the community. Respirators have been mandatory in public places in Austria for