Popular blue surgical face masks do NOT stop people from being infected with COVID-19

University of Waterloo researchers find most cloth masks are only 10% effective. Researchers warn most cloth masks do not cover the face properly. N95 or KN95 masks were found to be the most effective at filtering aerosols. Study also found that even 'moderate ventilation' matches the best of masks in terms of protection against COVID-19. Mask debate remains contentious in the country as delta variant spreads