A letter released today from 363 Canadian experts urging the prime minister, premiers, and CMOs to “update provincial COVID-19 guidelines, workplace regulations and public communication to reflect the science — COVID-19 spreads through inhaled aerosols.”  

They note “the evidence is now overwhelming — aerosol transmission of COVID-19 is common and is an important route of transmission. In suboptimally ventilated environments, infectious aerosols can accumulate in shared room air and reach dangerous concentrations. Control strategies targeting close-proximity transmission, such as physical distancing and effective face-fitted masks, are key to reducing short-range aerosol transmission risk. For transmission in shared room air, ventilation and air filtration are critical additional measures, as expelled aerosols build up in poorly ventilated spaces. We know that many workplaces, buildings and residences in our communities have substandard ventilation.”

Also notable: “The acknowledgement of aerosol transmission also calls into question the provincial directives for personal protective equipment for health care workers and other essential workers. Most health care workers and essential workers in Canada continue to use “droplet and contact precautions,” wearing poorly-fitted surgical masks, even in high-risk settings.”