Debate continues over possibility of airborne COVID

A University of Saskatchewan microbiologist is speaking out against the idea of COVID-19 commonly spreading through the air.

Dr. Joseph Blondeau told Gormley on Friday there isn’t enough evidence to make a solid conclusion just yet, but Blondeau leans towards the virus not aerosolizing.

He thinks it’s important to make a distinction between what the virus is capable of doing and what it commonly does.

“Some of the conditions under which some evidence of aerosolized transmission of the virus have been touted have been under experimental conditions, and may not necessarily represent the real world in terms of what happens on a day-to-day basis,” he explained.

“You could aerosolize a brick if you want to … but it may not necessarily represent what the day-to-day activities are.”

He compared how many people the average COVID-19 person goes on to infect with other viruses as evidence that it’s more likely spread through droplets.

Blondeau used an epidemiological term called the “Arnot Value.”

“It refers to the contagiousness of an infectious disease and how likely one person would be to infect another individual. If we look at viruses that are truly airborne — measles and chickenpox for example — they have Arnot Values as high as 18 to 20, meaning one individual can infect 18 to 20 other individuals,” he explained.

“For COVID, that Arnot Value has typically been down in that two to three range … The likelihood that it is truly aerosolized has not been borne out in these estimates,” he finished.

World Health Organization’s Perspective

The World Health Organization is acknowledging the possibility that COVID-19 might be spread in the air under certain conditions after more than 200 scientists urged the agency to do so.

In an open letter published this week in a journal, two scientists from Australia and the U.S. wrote that studies have shown “beyond any reasonable doubt that viruses are released during exhalation, talking and coughing in microdroplets small enough to remain aloft in the air.”

The researchers, along with more than 200 others, asked national and international authorities to adopt tougher protective measures.

The organization has long dismissed the possibility that the coronavirus is spread in the air except in rare and specific circumstances.

In a change to its previous thinking, WHO noted on Thursday that studies evaluating COVID-19 outbreaks in restaurants, choir practices and fitness classes suggested the virus might have been spread in the air.

Airborne spread “particularly in specific indoor locations, such as crowded and inadequately ventilated spaces over a prolonged period of time with infected persons, cannot be ruled out,” WHO said.

On the other side of the issue, officials also pointed out that other modes of transmission – like contaminated surfaces or close contacts between people in such indoor environments – might also have explained the disease’s spread.

— With files by The Associated Press