An Alberta doctor is clarifying her position after the province's governing party posted an excerpt from an article she wrote about COVID-19 transmission in schools that received an angry backlash online.
"I think that sentence was misunderstood by many people," said Dr. Joan Robinson, a pediatric infectious disease physician at Stollery Children's Hospital in Edmonton.
"I accept some responsibility for that," she told CBC News on Thursday.
The sentence she's referring came from an opinion article published Wednesday in the Edmonton Journal.
The sentence was quoted in a post on the United Conservative Party Caucus Facebook page, which sought to reassure parents about the safety of students returning to class in the fall.
It reads: "Good handwashing prior to touching food or one's face and avoidance of close contact with others whenever practical are strategies that are likely to be effective; it is exceedingly rare and maybe not even possible to acquire the virus simply by being in the same room as an infected person."
The Facebook post quickly received hundreds of replies, many from people who interpreted the post to be contradictory to what they had understood from public health officials.
Robinson said the sentence, taken alone, might leave people with the wrong impression, but stood by the general point she was trying to make in the article.
"What I meant is the way you can get the virus by being in the same room as another person is if you touch an object that they touch or if you're in close contact with that person such that their droplets — that come from speaking, screaming, singing, whatever — come in contact with you," she said.
"I do not think there's evidence that the virus is truly airborne, which would imply that you could get infected simply by being in the same room with another person but not touching the same object and not coming very close to them."
That point — the likelihood of aerosol or airborne transmission of COVID-19 — was often mentioned among the comments on the UCP Facebook post.
And it's been a point of much debate, controversy and confusion for many weeks now, well beyond Alberta.
Is COVID-19 airborne?
The terms "aerosol transmission" and "airborne" can mean different things to different people. (More on that in a moment.)
But in essence, the question boils down to whether enough of the virus that causes COVID-19 can live on tiny, exhaled droplets that linger in the air long enough and in sufficient quantities to infect other people.
These tiny droplets stand in contrast to the larger droplets that are known to be a source of transmission, which are relatively heavy and tend to fall to the ground within a couple of metres of the person who emits them. (This is why public health officials recommend staying two metres apart.)
On July 6, more than 200 scientists from nearly three dozen countries published an open letter calling on the World Health Organization (WHO) and other public health bodies to acknowledge "airborne" transmission as a potential driver of the pandemic.
On July 9, the WHO softened its position ever so slightly, with an updated statement saying aerosol or airborne transmission "cannot be ruled out" but also that, in cases where it may have occurred, the transmission could also be explained by other means.
Many public-health experts in Canada have been hesitant to use the term "airborne" in conjunction with COVID-19, noting the evidence is quite weak compared with the known methods of transmission, including direct contact with larger droplets or contaminated surfaces.
In response to the open letter, British Columbia's provincial health officer Dr. Bonnie Henry said the authors, in her view, were trying "to foment a bit of controversy" in the medical and research community but the issue was really "a little bit of a tempest in a teapot."
The available evidence, she said at the time, continues to suggest the novel coronavirus spreads predominantly through larger droplets and on surfaces.
"It is important to continue to look at the data, to look at where we're seeing transmission events and adapt if we need to and put in additional measures," she added.
Colin Furness, an epidemiologist with the University of Toronto, said the term "airborne" can also lead people to conflate COVID-19 with other diseases, such as measles, which are much more highly transmissible.
"To the general public, the word (airborne) can be pretty confusing because it suggests that COVID is going to come through the keyhole and get you in your sleep. And well, it isn't," he said shortly after the open letter was published.
"No one is suggesting COVID behaves anything like measles.... That's not the point (the scientists) are trying to make."
Definitions of 'airborne'
Public Health Ontario has also noted the definition of "airborne" can vary.
"Referring to a pathogen as 'airborne,' in a hospital setting, refers to the predominant mode of transmission," the agency wrote in a review of the open letter.
"Airborne transmission occurs when airborne particles remain suspended in the air, allowing them to travel on air currents and then inhaled by others in the vicinity or at further distances away from the source. By this definition, COVID-19 is not an airborne infection (such as measles or tuberculosis)."
The review goes on to say that much of the "public discussion and controversy" generated by the open letter "can be attributed to different use of terminology."
"There is broad agreement among the scientific community that the predominant mode of COVID-19 transmission is by the droplet route within close contact," it adds.
Phil Lagacé-Wiens, a professor of medical microbiology at the University of Manitoba, agreed.
"It's important to make a distinction between what the general public thinks of as 'airborne' and what the medical language tells us," he said in an interview Thursday.
"In the medical context, only diseases that can be spread long, long distances from the infected person are called 'airborne' and the others are called 'droplet' transmission. It's well established that COVID-19 is a disease that is transmitted through these large droplets, not through tiny, little, airborne particles."
Transmission of COVID-19 through the air at distances beyond two or three metres has been reported in the context of some medical procedures and in indoor settings with "abnormal ventilation patterns" such as air conditioners that blow a lot of air in one direction, he said.
"But in day-to-day events, these sorts of things don't really happen," he said. "And so we can pretty confidently conclude that transmission of COVID-19 occurs in a pretty tight circle, about two metres."
CBC News asked Alberta Health if the UCP Facebook post conflicted with the province's public-health advice, and the inquiry was directed to Steve Buick, the press secretary for Health Minister Tyler Shandro.
In an email, Buick said "it's clearly for Dr. Robinson or any other expert to explain their statements if there's any question about them."
"The op ed doesn't change anything in our guidance to the public or the schools," he added.
Asked whether the UCP caucus stands by the Facebook post and what it believes about the risk for transmission of COVID-19 in schools, a spokesperson responded with a statement that didn't directly answer the questions.
"Dr. Robinson is a highly respected pediatric infectious disease physician at the Stollery Children's Hospital," the statement reads."We're not interested in responding to NDP union boss Gil McGowan's, and other twitter activit's [sic] smears of Dr. Robinson," the statement added, appparently in reference to this tweet from the president of the Alberta Federation of Labour.
"The Government's plan is developed using the best scientific and medical advice of Alberta health experts, including Chief Medical Officer of Health, Dr. Deena Hinshaw," the UCP caucus statement added.
During her regular COVID-19 press conference Thursday afternoon, Hinshaw said she read the opinion article by Dr. Robinson, and the clarification note Robinson later added, and saw no problems with the information that was presented.
"What I understood the author to say was that this virus is not transmitted in a way like measles is, which is that very far distance, very long duration airborne transmission," Hinshaw said.
"Her perspective would be very similar to mine," she added.