Toronto (TIP): Canada has quietly revised its guidelines on how COVID-19 spreads to include the risk of aerosol transmission, weeks after other countries and international health organizations acknowledged the airborne threat of the coronavirus. The Public Health Agency of Canada (PHAC) updated its guidance without notice this week, making mention of the risk of transmission from aerosols — or microscopic airborne particles — for the first time. “SARS-CoV-2, the virus that causes COVID-19, spreads from an infected person to others through respiratory droplets and aerosols created when an infected person coughs, sneezes, sings, shouts, or talks,” the updated guidance said.

“The droplets vary in size from large droplets that fall to the ground rapidly (within seconds or minutes) near the infected person, to smaller droplets, sometimes called aerosols, which linger in the air under some circumstances.” The federal agency’s guidelines previously said the virus spreads only through breathing in respiratory droplets, touching contaminated surfaces and common greetings like handshakes and hugs. “We are continually reviewing new evidence and research as it emerges during the pandemic, and this new evidence guides our response to Canadians,” a spokesperson for PHAC said in a statement to CBC News.