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Researchers look at humidity as a weapon in the fight against airborne viruses – Times Colonist

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The ongoing fight against the COVID-19 pandemic could get a boost if Canadians paid more attention to the relative humidity levels in public and private spaces, according to a growing body of international research.

Doctors, scientists and engineers agree that sufficient indoor air moisture levels can have a powerful but little-understood effect on the transmission of airborne diseases. While the novel coronavirus that causes COVID-19 is currently treated as one that’s transmitted through droplet infection rather than the air, research on exactly how it passes between humans is still underway.

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Most buildings, however, fall short of the recommended threshold of 40 to 60 per cent relative humidity, particularly in countries with colder, dryer climates such as Canada.

Addressing the issue now, they contend, could confer some immediate short-term benefits and offer a powerful tool for warding off similar epidemics in the future.

“Transmission is greater in dry air, infectivity is higher in dry air, and the ability of a human being to fight infection is impaired,” said Dr. Stephanie Taylor, a graduate of and lecturer at Harvard Medical School. “Any one of those would be important, but all three of them are in play.”

Taylor concedes that the notion may seem counter-intuitive, saying the idea of humidity conjures images of fetid swamps and disease-bearing mosquitoes. But she said a growing body of research has suggested that relative humidity levels that are much more comfortable for humans offer a host of benefits.

She said airborne particles carrying viruses can travel farther in air that isn’t sufficiently hydrated. For reasons researchers are still probing, she also said viruses seem to be more infectious in those dryer conditions as well.

Dr. Samira Mubareka, a medical microbiologist at Toronto’s Sunnybrook Hospital and a member of a team that isolated the novel coronavirus, previously helped conduct research on the effect of temperature and humidity on influenza strains.

The research, which evaluated data from Toronto over a roughly five-year period, found higher humidity levels seemed to help create less favourable conditions for viruses to thrive, particularly in colder overall temperatures.

“It was in that range of 50 to 60 (per cent) where we saw the least amount of transmission,” she said.

Researchers also said relative humidity levels have an effect on the human body’s natural infection-fighting functions.

Karen Bartlett, a professor at the University of British Columbia’s School of Population and Public Health, said proper hydration is necessary to ensure the health of everything from mucus membranes to eyes and skin.

“If we are between that 40 and 60 (per cent) relative humidity, we are also protecting our buildings and making it more comfortable for us,” she said.

But according to the international body that sets standards for the built environment in many countries including Canada, those benefits can’t be obtained in the majority of public and private buildings.

Robert Bean, a Calgary-based indoor climate consultant and distinguished lecturer with the American Society of Heating, Refrigerating and Air-Conditioning Engineers, said Canadian buildings are advised to maintain humidity levels between 35 and 55 per cent.

But he said Canada’s relatively cold, dry climate can make it difficult to sustain those levels, particularly in older buildings.

The greater the difference between indoor and outdoor humidity levels, he said, the greater the tendency for the inside air to flow outward and cause condensation, which can in turn lead to mould and other potential hazards.

This tendency is at its peak in older buildings such as schools, he said, but added poor understanding of building standards is also a risk factor.

Bean said international research has shown that less than five per cent of buildings currently comply with ASHRAE’s standard dictating the environmental conditions for human occupancy, which includes relative humidity as a factor.

“If you had any other industry with such low knowledge of their standards, that industry would collapse,” he said.

But Bean said the trend is slowly starting to change, in part due to a growing understanding of the overlap between the engineering and medical communities.

“This whole issue with the virus is bringing up the importance of the built environment,” he said. “It exposes the weaknesses that we have in the relationship between the building sciences and the health sciences.”

Taylor said individuals coping with self-isolation or practising physical distancing could benefit from boosting relative humidity levels in their own environments and called on public spaces to make such efforts a priority moving forward.

But Mubareka stopped short of echoing her recommendations, saying too much is unknown about COVID-19 at this point.

“I wouldn’t be surprised if the conditions were very similar, but until it’s properly tested, I personally would hesitate to recommend the general public start implementing things of that nature,” she said.

Mubareka said all evidence available to date suggests measures to protect against droplet infections remain the best line of defence against COVID-19, particularly regular hand-washing, the use of masks for health-care workers and those showing symptoms, and physical distancing for the rest of the public.

This report by The Canadian Press was first published April 3, 2020.

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Canada to donate up to 200,000 vaccine doses to combat mpox outbreaks in Africa

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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.

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How many Nova Scotians are on the doctor wait-list? Number hit 160,000 in June

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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.

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Newfoundland and Labrador monitoring rise in whooping cough cases: medical officer

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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.

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