IN the wake of the World Health Organization acknowledging some risk of airborne transmission of COVID-19 in poorly ventilated or crowded indoor spaces, Manitoba’s top doctor emphasized the virus usually spreads via droplets.
The coronavirus can spread through the air in certain crowded, indoor settings and areas that aren’t well ventilated, the WHO stated in updated transmission guidelines April 30, because aerosols (tiny droplets carried through the air) can "remain suspended in the air or travel farther than one metre."
The WHO still says the virus spreads mainly via droplets when people are in close contact with each other.
The organization, which is an agency of the United Nations, has previously been criticized for being slow to recognize the threat of airborne transmission of COVID-19. The Public Health Agency of Canada acknowledged the risk of airborne transmission in the fall.
Infectious diseases that are considered airborne — such as tuberculosis, chicken pox and measles — typically are transmitted in viral or bacterial particles that stay in the air a lot longer and can travel greater distances.
There is some evidence the COVID-19 virus can travel more than two metres, but in the majority of cases, a two-metre guideline for physical distancing, as well as mask-wearing and handwashing, is effective at stopping the spread, chief provincial public health officer Dr. Brent Roussin said Monday.
He was asked during a news conference how the updated WHO guidelines affect Manitoba schools and other spaces where people are gathered indoors.
Roussin said he still recommends appropriate ventilation and opening windows when the weather permits, along with the existing advice to stay home, limit contacts, wear masks and stay at least two metres apart from others. But for the most part, the virus still spreads via droplets, he said.
"The issue here is that transmission of virus, just like really anything in medicine, is not binary," said Roussin.
"There is a bit of that grey area. Certainly, COVID is predominantly spread by droplet. That’s by far the transmission mechanism that this virus is spread by. In certain circumstances, there’s been reports of transmission wider than that two-metre distance," Roussin said.
"We wouldn’t classify it necessarily as airborne."
Katie May reports on courts, crime and justice for the Free Press.