TORONTO —
A new study looking at how long the novel coronavirus can survive on surfaces found that it can remain infectious on some surfaces — including bank notes — for at least 28 days, provided the temperature is right.
Published this week in the Virology Journal, the new paper describes how researchers tested the virus on several surfaces, including cotton and bank notes, at numerous temperatures in order to measure the lifespan of the virus under these different circumstances.
They found that the virus dies significantly faster on surfaces in hotter temperatures, and can survive on several non-porous surfaces for up to four weeks — much longer than previous studies have indicated.
Overwhelmingly, evidence has shown that the primary way COVID-19 is spread is through droplets and through sharing air with others, but that hasn’t stopped the fear of surface transmission. Hand washing is still one of the most important prevention methods that health officials tout.
Previous studies have looked at how long SARS-CoV-2, the virus that causes COVID-19, remains infectious on different surfaces, with some studies finding it to be a matter of hours, and others saying it could be days.
In this study, the surfaces researchers tested the virus on included Australian bank notes — which, like Canadian bank notes, are polymer — paper bank notes, glass, vinyl, stainless steel and cotton.
Researchers noted that they wanted to include money because it is an object that travels frequently between different people. Stainless steel, vinyl and glass are materials found in most public spaces, and cotton is often found in clothing and bedding.
When a virus gets onto a surface, it is often through a sneeze or through droplets expelled from the mouth. Researchers diluted SARS-CoV-2 “in a defined organic matrix […] designed to mimic the composition of body secretions” before placing it onto the materials to measure the longevity.
They noted in the paper that the concentration of the virus in each sample was high, it still “represents a plausible amount of virus that may be deposited on a surface.”
Samples of each material with the virus on it were placed into a “humidified climate chamber” so a set humidity of 50 per cent relative humidity could be maintained while the samples were tested at different temperatures and timeframes.
Samples were tested at 20, 30 and 40 degrees Celsius, and were inspected 1 hour, 3 days, 7 days, 14 days, 21 days and 28 days after the virus had first been introduced to the material.
Researchers found that at 20 degrees Celsius, the virus could survive for at least 28 days on every material except for cotton, the most porous of the materials tested.
SARS-CoV-2 couldn’t be detected on cotton after 14 days had passed.
“The majority of virus reduction on cotton occurred very soon after application of virus, suggesting an immediate absorption effect,” the report said.
Does this mean every bank note in our wallets could infect us? According to Colin Furness, an infection control epidemiologist at the University of Toronto, we shouldn’t jump straight to alarm.
“What we’re seeing empirically, clinically, with contact tracing, is that COVID is not spreading heavily through touch,” he said.
It is possible to contract the virus through surfaces, he said, “but it’s not happening very often.”
He said that earlier in the pandemic, when we had a looser understanding of the virus, there was a bigger fear of things like groceries or the mail in terms of surface transmission. But at this point, we have a greater understanding of how COVID-19 predominantly spreads.
“It’s shared airspace,” Furness said. “It’s droplet and aerosols and shared air with poor ventilation and prolonged contact. That’s how you get sick. That’s the thing to be scared of, which is why I’ve been very, very worried about indoor dining. And it’s not because you might touch contaminated cutlery. It’s because you’re in this room with a lot of other people and not wearing a mask and sharing air.”
This study carried out its experiments at a lab at the Australian Centre for Disease Preparedness, with the samples in complete darkness “to negate any effects of UV light” — just one way that the conditions of the experiments differed from real life.
“[This study] tells you what can happen under laboratory conditions,” Furness said.
A bank note in your pocket or your wallet is rubbing up against other things, he explained, not sitting undisturbed to measure the longevity of a virus. If surfaces are exposed to sunlight as well, that can aid with a faster decay of any virus on the surface.
These studies are the first step, he said, and then researchers “need to test in the real world. What is the real significance of this?
“And those numbers are usually quite different.”
The raw numbers of the study also don’t paint the full picture. Although the virus was still detectable on most surfaces at the 28 day mark, it reduced in concentration much faster than that.
“Viruses aren’t alive,” Furness said. “They can’t regenerate, they can’t metabolize or protect themselves as soon as they leave your body. As soon as you exhale some virus, the virus starts to die.”
The half-life of the virus (the time it takes for it to reduce by 50 per cent) on a paper bank note at 20 degrees Celsius was 2.74 days, showing the viral load decreases in concentration far faster than the 28 days would suggest. After 9.13 days, 90 per cent of the virus was gone.
On cotton, at 20 degrees Celsius, the half-life was 1.68 days, and it took 5.57 days for a 90 per cent reduction in the virus.
Five to nine days is still a long time for a virus to remain infectious on a surface, although it’s still unknown at what point the viral load would be too small to actually make a person ill.
Researchers said in the paper that the extended half-life in this study compared to others could be down to the controlled conditions that they created for the experiment.
While this study does not mean we should panic about surface transmission, which remains one of the rarer ways to transmit the virus, it does provide insight into how temperature interacts with the virus’ survivability.
Researchers did not measure any of the virus samples at less than 20 degrees Celsius, but they observed how much the rate of virus decline sped up when the temperature increased from 30 to 40 degrees Celsius. Extrapolating backwards from that, they posit that if the temperature dropped significantly from 20 degrees Celsius, the lifespan of the virus on various surfaces could increase.
“This data could therefore provide a reasonable explanation for the outbreaks of COVID-19 surrounding meat processing and cold storage facilities,” they theorize.
Furness said the temperature is a huge factor when it comes to a virus’ survivability.
“In the winter, in freezing temperatures, COVID will last [longer] on surfaces,” he said.
“So if you’re going to a playground in the winter, it can be quite worrisome. I wonder whether we’re going to see that COVID does spread more by touch in the winter. I can’t say that it does, but it’s entirely possible that it will.”
He said the concept of temperature is something that hasn’t been emphasized enough as Canada begins to tackle its second wave.
“It’s not just the numbers are going up,” he said. “Numbers are going up, while temperatures are going down.”
The best thing to do?
“We should continue to wash our hands and be vigilant,” Furness said. “In fact, during COVID, I would say the best outcome of washing your hands is actually so you don’t get any other colds that would make you afraid that maybe you have COVID.”
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.
