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.
PHAC did not immediately respond to CBC’s request for comment on the changes to the guidelines.
Change to guidelines ‘pretty major,’ aerosol expert says
“This is pretty major,” said Linsey Marr, one of the top aerosol scientists in the world and an expert on the airborne transmission of viruses at Virginia Tech. “The big difference now is that ventilation is important — distancing alone is not enough.”
CBC News pressed the federal agency last month on why it still made no mention about the risk of aerosols despite other international agencies doing so.
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 World Health Organization also came under fire in July after 239 scientists from 32 countries wrote an open letter calling on the United Nations agency to update its messaging on the risk of airborne transmission of the coronavirus.
The update to PHAC’s guidelines came after Canada’s Chief Public Health Officer Dr. Theresa Tam recommended the use of three-layer non-medical masks Tuesday to prevent the spread of COVID-19 ahead of winter weather that could bring more people together indoors.
“This is an additional recommendation just to add another layer of protection. The science of masks has really accelerated during this particular pandemic. So we’re just learning again as we go,” she said Tuesday.
“I do think that because it’s winter, because we’re all going inside, we’re learning more about droplets and aerosols.”
Marr said that updated PHAC guidance on three-layer non-medical masks was in line with the threat of aerosol transmission.
“If we were only concerned about large droplets, then pretty much almost any piece of single layer of fabric would work,” she said.
“But because we are concerned about aerosols, then we do need to think about the quality and fit of our masks and we know that having multiple layers improves the filtering performance of masks.”
WATCH | Linsey Marr speaks in July about evidence the coronavirus could be airborne:
A signatory of the letter urging the WHO to change its recommendations around COVID-19 airborne transmission says it would be wise to do as much as we can to slow down the virus. 6:00
Tam said Tuesday public health officials also wanted to emphasize that the public should wear a mask indoors when not with people in their household, another significant update to its guidance.
“That will help prevent droplets or aerosols more so than if you were just relying on the two metre distance,” she said. “Again, adding another layer.”
PHAC previously told CBC News in a statement on Sept. 24 that it was not updating its guidance on airborne transmission — even though it said there “have been situations where aerosol transmission in closed settings has occurred.”
Studies of superspreading events, such as a choir practice in Washington state, a call centre in South Korea and a restaurant in China, have supported the conclusion that some degree of transmission is occurring through the air. (Evan Mitsui/CBC)
The agency said at the time its guidance would remain the same: limit time spent in closed spaces, crowded places and close contact situations, while maintaining physical distancing, hand-washing and mask-wearing.
Addressing aerosol transmission requires many measures
“Distancing helps, masks help, ventilation helps — no one of these things is perfect,” Marr said.
Aerosol transmission, she said, would not be addressed by focusing on just one of these measures alone. “But when we combine all these things, we haven’t seen any outbreaks.”
PHAC also said in September that it was reviewing evidence on the topic and acknowledged that aerosols could be suspended in the air and infect others nearby, but it wasn’t known at what rate that happens and under what conditions.
“It’s important for the public health agencies to acknowledge this so that the public can now take appropriate steps to reduce transmission,” Marr said. “And there’s a lot of organizations like schools and businesses that look to the public health agencies for guidance.”
She said the updated PHAC guidelines would make it harder for these types of organizations to ignore the threat of aerosol transmission.
Studies of superspreading events, such as a choir practice in Washington state, a call centre in South Korea and a restaurant in China, have supported the conclusion that some degree of transmission is occurring through aerosols.
Virus particles were also found in the air at a nursing home outbreak in May in Montreal, where a faulty ventilation system may have been a source of transmission that infected 226 residents and 148 employees.
An outbreak at a spin studio in Hamilton, Ont., saw at least 85 people infected and prompted the city to announce new, enhanced guidelines for gyms and fitness centres including mandatory masking.
“The gym followed all the guidelines: they had distancing, they did hygiene, they had people wearing masks before and after,” Marr said, “but if it were just all large droplets, then the distancing and hygiene would be sufficient — but obviously, it wasn’t.”
“Because aerosols do play an important role in transmission and if you just distance and just do hygiene, that’s not enough.”
The Canadian government says it will donate up to 200,000 vaccine doses to fight the mpox outbreak in Congo and other African countries.
It says the donated doses of Imvamune will come from Canada’s existing supply and will not affect the country’s preparedness for mpox cases in this country.
Minister of Health Mark Holland says the donation “will help to protect those in the most affected regions of Africa and will help prevent further spread of the virus.”
Dr. Madhukar Pai, Canada research chair in epidemiology and global health, says although the donation is welcome, it is a very small portion of the estimated 10 million vaccine doses needed to control the outbreak.
Vaccine donations from wealthier countries have only recently started arriving in Africa, almost a month after the World Health Organization declared the mpox outbreak a public health emergency of international concern.
A few days after the declaration in August, Global Affairs Canada announced a contribution of $1 million for mpox surveillance, diagnostic tools, research and community awareness in Africa.
On Thursday, the Africa Centres for Disease Control and Prevention said mpox is still on the rise and that testing rates are “insufficient” across the continent.
Jason Kindrachuk, Canada research chair in emerging viruses at the University of Manitoba, said donating vaccines, in addition to supporting surveillance and diagnostic tests, is “massively important.”
But Kindrachuk, who has worked on the ground in Congo during the epidemic, also said that the international response to the mpox outbreak is “better late than never (but) better never late.”
“It would have been fantastic for us globally to not be in this position by having provided doses a much, much longer time prior than when we are,” he said, noting that the outbreak of clade I mpox in Congo started in early 2023.
Clade II mpox, endemic in regions of West Africa, came to the world’s attention even earlier — in 2022 — as that strain of virus spread to other countries, including Canada.
Two doses are recommended for mpox vaccination, so the donation may only benefit 100,000 people, Pai said.
Pai questioned whether Canada is contributing enough, as the federal government hasn’t said what percentage of its mpox vaccine stockpile it is donating.
“Small donations are simply not going to help end this crisis. We need to show greater solidarity and support,” he said in an email.
“That is the biggest lesson from the COVID-19 pandemic — our collective safety is tied with that of other nations.”
This report by The Canadian Press was first published Sept. 13, 2024.
Canadian Press health coverage receives support through a partnership with the Canadian Medical Association. CP is solely responsible for this content.
HALIFAX – The Nova Scotia government says it could be months before it reveals how many people are on the wait-list for a family doctor.
The head of the province’s health authority told reporters Wednesday that the government won’t release updated data until the 160,000 people who were on the wait-list in June are contacted to verify whether they still need primary care.
Karen Oldfield said Nova Scotia Health is working on validating the primary care wait-list data before posting new numbers, and that work may take a matter of months. The most recent public wait-list figures are from June 1, when 160,234 people, or about 16 per cent of the population, were on it.
“It’s going to take time to make 160,000 calls,” Oldfield said. “We are not talking weeks, we are talking months.”
The interim CEO and president of Nova Scotia Health said people on the list are being asked where they live, whether they still need a family doctor, and to give an update on their health.
A spokesperson with the province’s Health Department says the government and its health authority are “working hard” to turn the wait-list registry into a useful tool, adding that the data will be shared once it is validated.
Nova Scotia’s NDP are calling on Premier Tim Houston to immediately release statistics on how many people are looking for a family doctor. On Tuesday, the NDP introduced a bill that would require the health minister to make the number public every month.
“It is unacceptable for the list to be more than three months out of date,” NDP Leader Claudia Chender said Tuesday.
Chender said releasing this data regularly is vital so Nova Scotians can track the government’s progress on its main 2021 campaign promise: fixing health care.
The number of people in need of a family doctor has more than doubled between the 2021 summer election campaign and June 2024. Since September 2021 about 300 doctors have been added to the provincial health system, the Health Department said.
“We’ll know if Tim Houston is keeping his 2021 election promise to fix health care when Nova Scotians are attached to primary care,” Chender said.
This report by The Canadian Press was first published Sept. 11, 2024.
ST. JOHN’S, N.L. – Newfoundland and Labrador‘s chief medical officer is monitoring the rise of whooping cough infections across the province as cases of the highly contagious disease continue to grow across Canada.
Dr. Janice Fitzgerald says that so far this year, the province has recorded 230 confirmed cases of the vaccine-preventable respiratory tract infection, also known as pertussis.
Late last month, Quebec reported more than 11,000 cases during the same time period, while Ontario counted 470 cases, well above the five-year average of 98. In Quebec, the majority of patients are between the ages of 10 and 14.
Meanwhile, New Brunswick has declared a whooping cough outbreak across the province. A total of 141 cases were reported by last month, exceeding the five-year average of 34.
The disease can lead to severe complications among vulnerable populations including infants, who are at the highest risk of suffering from complications like pneumonia and seizures. Symptoms may start with a runny nose, mild fever and cough, then progress to severe coughing accompanied by a distinctive “whooping” sound during inhalation.
“The public, especially pregnant people and those in close contact with infants, are encouraged to be aware of symptoms related to pertussis and to ensure vaccinations are up to date,” Newfoundland and Labrador’s Health Department said in a statement.
Whooping cough can be treated with antibiotics, but vaccination is the most effective way to control the spread of the disease. As a result, the province has expanded immunization efforts this school year. While booster doses are already offered in Grade 9, the vaccine is now being offered to Grade 8 students as well.
Public health officials say whooping cough is a cyclical disease that increases every two to five or six years.
Meanwhile, New Brunswick’s acting chief medical officer of health expects the current case count to get worse before tapering off.
A rise in whooping cough cases has also been reported in the United States and elsewhere. The Pan American Health Organization issued an alert in July encouraging countries to ramp up their surveillance and vaccination coverage.
This report by The Canadian Press was first published Sept. 10, 2024.
