Top Canadian WHO adviser under fire after downplaying airborne threat of COVID-19

Top Canadian WHO adviser under fire after downplaying airborne threat of COVID-19-Milenio Stadium-Canada
Dr. John Conly, an infectious diseases physician and professor of medicine at the University of Calgary who also advises the World Health Organization, denies that aerosol transmission is a primary route of COVID-19 transmission, despite mounting evidence to the contrary. (Jennifer Lee/CBC)

An influential Canadian doctor and top adviser to the World Health Organization has come under fire from international experts for his controversial comments downplaying the risk of airborne spread of the coronavirus.

3M to make critical N95 masks at Brockville, Ont., plant

Dr. John Conly, an infectious diseases physician and professor of medicine at the University of Calgary, not only denied that aerosol transmission is a primary route of transmission, despite mounting evidence to the contrary, but also said that N95 masks can cause “harms” — including acne.

“Any time you look at benefits, you need to look at harms, of which there are many harms with N95s — and I think to ignore them you are at your peril,” Conly told a panel discussion at the University of Calgary on April 9 on the role of airborne transmission in the COVID-19 pandemic.

“There is acne, also issues with eczema, conjunctivitis, CO2 retention; there has been decreased O2 concentrations in pregnant women — many side-effects to this.”

His comments on oxygen and carbon dioxide have been largely discredited, with a 2014 study in the American Journal of Infection Control showing no significant differences in levels between pregnant and non-pregnant women wearing N95 masks.

The WHO’s position is there’s a possibility that aerosol transmission can lead to outbreaks of COVID-19 in certain situations. A change in stance from the WHO on aerosol transmission as the main driver would have huge implications on the need for increased air ventilation and better personal protective equipment for health-care workers and essential workers around the world.

Conly is one of Canada’s most experienced infectious diseases experts who was once head of the department of medicine at the University of Calgary and the medical director for infection prevention at Alberta Health Services.

He also holds considerable global influence in the pandemic as the chair of the WHO’s Infection Prevention and Control Research and Development Expert Group for COVID-19, which makes key decisions on the research that informs the WHO’s recommendations.

“We absolutely know there are situational airborne settings,” he added during the panel discussion. “But to be able to say that it is the only and predominant means, I think we need better scientific evidence.”

Conley carries ‘a lot of weight’ with WHO

The WHO has been criticized in the past for its reluctance to acknowledge aerosol transmission — or microscopic airborne particles — as a primary driver of the pandemic, and experts say Conly is at the heart of the issue within the organization.

“Frankly, I think he just can’t admit he’s wrong,” said Linsey Marr, one of the top aerosol scientists in the world and an expert on the airborne transmission of viruses at Virginia Tech in Blacksburg, Va.

“He does carry a lot of weight with WHO, and unfortunately I think his thinking is still stuck in what we knew 20 or 30 years ago and hasn’t updated with what we’ve learned since then — and especially what we’ve learned over the past year.”

Global acknowledgement of airborne spread

The United Nations agency also came under fire in July after 239 scientists from 32 countries wrote an open letter calling on it to update its messaging on the risk of airborne transmission of the coronavirus.

The WHO amended its guidelines days after the letter and acknowledged the possibility that aerosols can lead to outbreaks of COVID-19 in places such as choir practicesrestaurants and fitness classes.

The U.S. Centers for Disease Control and Prevention (CDC) updated its guidelines in early October to include that COVID-19 can sometimes be spread by airborne transmission, after mistakenly posting and later removing a draft version of guidelines in late September.

The CDC also updated its guidelines to say the risk of COVID-19 infection from surfaces is now officially considered low — meaning disinfecting groceries, wiping down packages and cordoning off playgrounds are likely unnecessary.

The Public Health Agency of Canada (PHAC) then quietly updated its guidance without notice in November, weeks after other countries and international health organizations, making mention of the risk of aerosol transmission for the first time.

PHAC went another step further and released further recommendations for Canadians on April 12 aimed at reducing the spread of aerosol transmission of COVID-19 and the need for adequate ventilation and air filtration to reduce the number of virus particles in the air.

Dr Theresa Tam-Mielnio Stadium-Canada
An update to Public Health Agency of Canada guidelines on the risk of aerosol transmission came after Dr. Theresa Tam, the country’s chief public health officer, recommended the use of three-layer non-medical masks in November to prevent the spread of COVID-19. (Sean Kilpatrick/The Canadian Press)

Science ‘very strong’ in favour of aerosol transmission

“The science is very strong to support aerosol transmission,” said infectious diseases specialist and medical microbiologist Dr. Raymond Tellier, who is also an associate medical professor at McGill University in Montreal.

“We keep having example after example, and the objections are becoming increasingly unconvincing.”

After the University of Calgary panel discussion, CBC News spoke to Conly, who said he was just one voice among many at the WHO. He stressed that the way the virus transmits is “very complex” and that the “majority” of transmission occurs through “close contact.”

“Social distancing, or physical distancing as some call it, and hygiene, cleaning and disinfection of surfaces. That’s where our focus should be,” he said. “The science about how it’s transmitted and where it goes, it will get itself sorted out.”

Conly was an author of a recent preprint study funded by the WHO that refuted the notion of aerosols as a primary mode of spread for the virus because “the lack of recoverable viral culture samples” from the air “prevents firm conclusions on airborne transmission.”

But in response to that study, which has not yet been peer-reviewed, a group of researchers — including Canadian epidemiologist Dr. David Fisman — published a comment in The Lancet that called into question its conclusion.

The researchers present 10 reasons why they conclude the virus that causes COVID-19 is primarily transmitted through the air, including superspreading events, long-range infections, the higher risk of indoor transmission and the fact that virus particles have been detected in the air.

The paper concludes that casting doubt on airborne transmission of the virus amounts to “scientific error” and that there is “consistent, strong evidence” that it spreads via aerosols, which are “likely to be dominant” over droplet and surface transmission.

“If you don’t include airborne, how are we in the middle of the global pandemic?” said Kimberly Prather, an atmospheric chemist and aerosol scientist at the Scripps Institution of Oceanography in San Diego, Calif.

“How do you explain outdoor versus indoor? How do you explain superspreader events? How do you explain everyone that shares the room and never touches each other or gets close to each other gets infected? I mean, you can’t.”

Prather, who went head-to-head with Conly at the University of Calgary panel earlier this month in favour of airborne transmission, was one of the co-authors of The Lancet comment that argued against his preprint article and a signatory of the letter to the WHO in July.

“The evidence just keeps coming in every day … there has not been a single paper that has pointed out why it isn’t aerosols,” she said.

“The fact that the [WHO] is not just shouting that from the mountaintops to save lives is, quite frankly, disappointing.”

COVID-19 masks-Milenio Stadium-Canada
Kimberly Prather, an atmospheric chemist and aerosol scientist at the Scripps Institution of Oceanography, says the evidence on aerosol transmission continues to grow and that Conly’s reluctance to acknowledge it, combined with his influence at the WHO, has implications for global public health guidelines. (Ben Nelms/CBC)

A recent study published by the U.S. Centers for Disease Control and Prevention showed that a singer at a church in Australia in July was able to infect several others from a distance of more than 15 metres indoors, while a second CDC study found an infection occurred in a New Zealand quarantine hotel in September after an exposure time of less than a minute in an open doorway.

And a recent outbreak at a gym in Quebec City where physical distancing and mask use were not enforced has been linked to more than 500 COVID-19 cases and become one of the largest recorded superspreading events in Canada.

Prather said Conly’s reluctance to acknowledge aerosol transmission as a main driver of the pandemic, combined with his influence at the WHO, has implications for global public health guidelines — such as for hospitals or schools.

“He has tremendous power,” she said. “What else is it going to take? Because just the amount of evidence in this short of a time period is incredible.”


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