Evolution of SARS-CoV-2, animal-to-human transmission, hospital capacity remain unknowns, experts say
In early 2020, as Dr. Samira Mubareka was following global updates on a strange new virus first reported in China, people with pneumonia-like symptoms started showing up in her hospital in Toronto.
One of the patients that came to Sunnybrook Health Sciences Centre was a man who’d travelled back from Wuhan. He was quite sick — more so than others who’d proven to be false alarms, Mubareka thought.
Inside Sunnybrook — a stately, sprawling hospital campus in one of Toronto’s toniest neighbourhoods — a newly developed diagnostic test confirmed what she and others suspected: the man had Canada’s first official case of what’s now known as COVID-19.
“The fact that it came as early as January, it lit a fire,” Mubareka later recalled.
While dressed in full protective gear, the microbiologist and infectious diseases specialist took samples from the patient’s isolation room. Her team was then able to culture the virus from several specimens inside a Level 3 containment facility — just one piece of the global effort to better understand SARS-CoV-2.
Not long after, on March 11, 2020, the World Health Organization declared a global pandemic. One day later, Mubareka’s team officially announced they’d isolated the virus behind it, joining other global scientists in offering hope that the world would be able to develop vaccines and treatments.
“Since then, we’ve just been following the virus around, whether it’s been variants of concern that have emerged in fairly rapid sequence, and finally following it into animals,” Mubareka said.
Two years into a pandemic that’s still raging around much of the globe, scientists like her are striving to unpack what makes this mysterious pathogen tick. Leading vaccines have proven remarkably effective at keeping severe disease at bay, yet SARS-CoV-2 remains a formidable foe — a mutating shapeshifter that’s evading our defences and capable of spreading at rapid rates rarely seen among other viruses.
Despite a surge in research, leading Canadian virologists and front-line physicians say burning questions remain over how the coronavirus operates and where this pandemic is heading.
Why are certain people so susceptible to infection, or serious illness? How will this virus continue to evolve? Which vaccines, drugs and public health strategies will protect our population from future variants? And where will SARS-CoV-2 show up next?
“There are just so many things we have to stay on top of,” Mubareka said.
Why does SARS-CoV-2 cause such a range of health impacts?
Two years’ worth of research into SARS-CoV-2 has painted an alarming picture of its uncanny ability to impact whole-body health. Studies have linked infections to a host of multi-organ issues, impacting everything from the brain to the gut to the heart, along with the entire circulatory system that pumps blood through your body.
Amid all the dire possible impacts, questions remain over why some people wind up with barely a sniffle, while others are ravaged by COVID-19.
Dr. Srinivas Murthy, a researcher on childhood infections and an associate professor in the University of British Columbia’s faculty of medicine, said that aside from whether someone is vaccinated or not, being elderly remains the clearest predictor of someone’s potential for severe COVID.
“Nothing impacts how you do with this virus more than age,” he said. “That’s corrected for how sick you are, how many comorbidities you have, and so on.”
But it’s not yet clear why this trend is seen at a staggering level beyond other viruses, which typically impact very young children to the same degree, he noted.
There are early signals that genetic differences might help explain why some people get hit so much harder than others, with one recent paper finding more than a dozen markers in those who developed severe COVID-19 — paving the way, potentially, for targeted treatments.
Then there’s long COVID — cases where people get over their initial infection but suffer lasting post-viral impacts, from cognitive difficulties to extreme fatigue. Those reactions seem to strike people more broadly, yet the condition remains little understood, with no known cure.
What’s the future for COVID-19 vaccines and treatments?
Humanity’s ability to ward off the worst outcomes from COVID has improved over the last two years, with a slate of vaccines, personal protections, medications and an ever-evolving treatment plan all playing a role.
But while vaccinations in particular have changed the course of the pandemic — offering high levels of protection against severe diseases — what form they’ll take in the future isn’t set in stone, said Dr. Alexander Wong, an infectious disease physician and clinician-researcher with the Saskatchewan Health Authority.
Some researchers are developing shots that could potentially target a variety of coronaviruses, not just SARS-CoV-2; other teams are exploring vaccines inhaled through the nose in hopes of curbing infections at the source by targeting the virus’s respiratory entry points.
There are also questions over whether vaccines will be tailored to emerging variants, and how often booster shots might be needed to prevent immunity from waning over time.
Which treatments will become standard going forward is also shifting, with antivirals increasingly part of the equation as research teams race to develop new and better drugs to ward off serious health impacts.
“There are just so many unknowns about what this is going to look like,” Wong said.
Which public health measures work best?
Multiple experts also stressed the importance of figuring out which public health measures worked best — and which ones were a flop — so governments can put in place the best plans to live with this virus in the long term.
That could be particularly crucial given the looming threat of future variants that may be more contagious, more pathogenic or more capable of evading our current vaccines.
“What actually worked to help the bottom line, which was to prevent deaths and hospitalizations? I don’t think we have a good answer to that,” said Dr. Sumon Chakrabarti, an infectious diseases specialist at Trillium Health Partners in Mississauga, Ont.
He said there’s “no doubt” vaccines are important, but that more evidence is needed to understand what role mask-wearing played — particularly since mask mandates across much of the country did little to stop the unprecedented infection rates seen in the Omicron-driven wave.
WATCH | Experts warn about returning to ‘normal’ too soon:
Society-wide lockdowns, several experts agreed, were a last-ditch option in the early pandemic that proved not to be a sustainable or successful approach for curbing virus transmission long-term.
“Even if restrictions worked, it protected the laptop class,” said Chakrabarti, who often treated essential workers from local big box stores or factories who were battling COVID.
“If you look at the death rates, during lockdowns, people still died. And the people who died were people who couldn’t work from home or isolate,” said Murthy. “Lockdowns were a public health failure, but we used them as a last resort, because we couldn’t respond in any other way.”
A better approach for the future, he stressed, is a shift in how society strives to curb virus transmission more broadly, by focusing on measures like improving ventilation throughout indoor settings.
“In the 1800s, we sanitized water. In the 1900s, we sanitized streets,” he said. “In the 21st century, are we going to sanitize our air?”
How will health-care systems grapple with COVID-19 going forward?
A burning question for Jason Kindrachuk, a microbiologist with the University of Manitoba, is how health-care systems will function if seasonal waves of COVID wind up layering on top of other respiratory illnesses.
“It’s not like COVID replaced influenza. It did for the last two years, because we were able to keep influenza at bay. But without restrictions, we don’t know the toll on an annual basis,” he said.
“How much of that can we continue to add up before the health-care system can’t care for the people that we’ve traditionally been able to?”
How COVID competes with flu is one thing, and there’s also a pre-existing issue in health care: even before the pandemic hit, hospitals faced a capacity crunch while grappling with high levels of patients, including those who fill beds simply because they’re waiting for spots in retirement homes or long-term care facilities.
“It’s all an interlocking system,” said Chakrabarti. “If one aspect has stress on it, it’s going to affect the whole system.”
WATCH | How Canadian researchers are preparing for the next pandemic:
How is this virus transmitting between species?
While many scientists are striving to understand the pandemic’s future impact on humans, Sunnybrook’s Mubareka is keeping her focus on animals, since our health is ultimately connected.
A crucial question going forward, she said, is which animals are susceptible to SARS-CoV-2 infections, and how various species that are already getting infected — like white-tailed deer — are being exposed to the virus.
As part of a team of Canadian scientists, Mubareka recently helped produce preliminary research that outlined the discovery of a heavily mutated lineage of SARS-CoV-2 within Canadian deer populations, and an apparent instance of deer-to-human virus transmission.
But that paper is just the tip of the iceberg, with so much still unknown about how this virus is spreading throughout the animal kingdom.
“We need to understand where coronaviruses are in nature and what the behaviours are that we undertake with zoonotic pathogens that lead to spillover events,” said Kindrachuk. “It’s something we understand somewhat, but we don’t fully know how to mitigate those risks.”
Angela Rasmussen, a virologist and researcher with the University of Saskatchewan’s Vaccine and Infectious Disease Organization, said more research is underway in Canada to answer key questions about this virus’s evolution within animal hosts.
“Are those variants a threat to the human population? We don’t know. Are there threats to animal populations? I mean, that’s something that has huge implications for food security, for the economy, for animal welfare, for the ecology,” she warned.
“So I think that a better understanding of … which animals may actually have SARS-CoV-2 circulating in them already is going to be really crucial going forward for our long-term prospects of controlling [this virus].”
Canada considering smallpox vaccine for monkeypox cases, says Dr. Theresa Tam
OTTAWA — The risk posed by monkeypox is low, but nearly everyone in Canada is susceptible because routine vaccination against smallpox ended decades ago, top public health officials said Friday.
Monkeypox is a rare disease that comes from the same family of viruses as variola. That virus causes smallpox, which the World Health Organization declared eradicated around the globe in 1980. It is also linked to the vaccinia virus used in the smallpox vaccine.
The Public Health Agency of Canada, which is investigating about two dozen possible cases of monkeypox on top of two confirmed cases in Quebec, says it is spread through prolonged close contact. That includes through direct contact with an infected person’s respiratory droplets, bodily fluids or sores, and is not very contagious in a typical social setting.
The B.C. Centre for Disease Control said Friday that it is not investigating any suspected cases or possible contacts of monkeypox in the province after having ruled out two potential contacts.
Canada’s chief public health officer Dr. Theresa Tam said the federal public health agency does not know how widespread the disease has become in the country.
Monkeypox is typically milder than smallpox and can cause fever, headache, muscle aches, exhaustion, swollen lymph nodes and lesions all over the body.
There is global evidence that smallpox vaccines can offer protection against monkeypox.
But Canada stopped routinely immunizing people against smallpox in 1972.
Tam’s deputy, Dr. Howard Njoo, said this means everyone is susceptible to monkeypox.
“I would say, generally, the entire population is susceptible to monkeypox,” Njoo said Friday.
Canada does keep a small stockpile of smallpox vaccine in case of a biological incident, like a laboratory exposure.
A smattering of cases in the United Kingdom prompted that country to begin offering the vaccine to health workers and close contacts of confirmed cases.
Tam said Canada is considering a similar strategy.
“Quebec had some interest in terms of the contacts so that is under discussion right now, but of course we need to know some of the epidemiology as quickly as possible,” Tam said.
She would not say how many doses of the smallpox vaccine Canada has available, citing security reasons.
Public Services and Procurement Canada put out a tender last month to purchase 500,000 doses of the Imvamune smallpox vaccine on behalf of the Public Health Agency of Canada from 2023 to 2028.
“Although smallpox disease is currently considered to be eradicated, PHAC is procuring a stockpile of the vaccine to immunize Canadians against smallpox disease should a risk ever arise where smallpox is intentionally or unintentionally released,” the tender read.
Health Canada has also approved that vaccine, from Danish biotech company Bavarian Nordic, for use to prevent monkeypox.
The company announced Thursday it had secured a deal with an unnamed European country to supply its vaccine in response to monkeypox cases.
There is still a sense of mystery surrounding the sudden appearance of the virus in Canada, the U.S., Australia and several parts of Europe.
“Not many of these individuals are connected to travel to Africa where the disease is normally seen, so this is unusual. It’s unusual for the world to see this many cases reported in different countries outside of Africa,” Tam said.
Canadian health systems are casting a wide net in their search for more cases, she said, because there is not enough known about why the virus is suddenly cropping up around the globe.
“There’s probably been some hidden chains of transmission that could have occurred for quite a number of weeks, given the sort of global situation that we’re seeing right now,” she said.
Njoo said global public health authorities need to be open to the idea that monkeypox is evolving, and transmission may have changed as well.
For now, samples from suspected cases are being sent to the National Microbiology Laboratory in Winnipeg, but PHAC is working with provinces to set up more local diagnostics.
This report by The Canadian Press was first published May 20, 2022.
Laura Osman, The Canadian Press
Persisting coronavirus could drag out COVID-19 symptoms – National Geographic
Most COVID-19 patients recover from their acute infection within two weeks, but bits of the virus don’t always disappear from patients’ bodies immediately. Now a new study, one of the largest focusing on hospitalized COVID-19 patients, shows that some patients harbor these viral remnants for weeks to months after their primary COVID-19 symptoms resolve.
The study suggests that when the genetic material of the virus, called RNA, lingers in the body longer than 14 days, patients may face worse disease outcomes, experience delirium, stay longer in the hospital, and have a higher risk of dying from COVID-19 compared with those who cleared the virus rapidly. The persistence of the virus may also play a role in long COVID, the debilitating suite of symptoms that can last for months. Estimates suggest between 7.7 and 23 million people in the United States alone are now affected by long COVID.
Without immunity from vaccination or a previous infection, SARS-CoV-2—the virus that causes COVID-19—replicates and spreads throughout the body and is shed through the nose, mouth, and gut. But for most infected people, virus levels in the body peak between three and six days after the original infection, and the immune system clears the pathogen within 10 days. The virus shed after this period is generally not infectious.
Even after accounting for disease severity, whether the patients were intubated, or had underlying medical comorbidities, “there is something here that signals that patients who are persistently PCR positive have worse outcomes,” says Ayush Batra, a neurologist at Northwestern University Feinberg School of Medicine, who led the new study.
Batra’s study shows that patients who had prolonged shedding during an acute infection risk more severe outcomes from COVID-19, says Timothy Henrich, a virologist and immunologist at the University of California, San Francisco who was not involved in the new research. But the study doesn’t investigate whether this persistent virus is directly responsible for long COVID.
“There are multiple leading hypotheses out there about the cause of long COVID, including viral persistence, and it may be that there are multiple pathways at play, perhaps to some varying degree in any one person,” says Linda Geng, a doctor at Stanford Health Care who co-directs a newly opened Post-Acute COVID-19 Syndrome Clinic for treating long COVID sufferers.
Persisting virus causes worse COVID-19 outcomes
Batra and his team began studying persistent coronavirus infections after observing that some patients who were returning to the hospital were still testing positive for the virus four or five weeks after they were diagnosed with the initial infection.
For their new study, the team analyzed 2,518 COVID-19 patients hospitalized in the Northwestern Medicine Healthcare system between March and August 2020. They focused on PCR tests, which are considered the gold standard, because such tests detect genetic material from the virus and so are highly sensitive and less likely to return false negatives.
The team found that 42 percent of patients continued to test PCR positive two weeks or longer after their initial diagnosis. After more than 90 days, 12 percent of the persistent shedders were still testing positive; one person tested positive 269 days after the original infection.
Viral persistence has been noted before in previous smaller studies. Researchers showed that even patients without obvious COVID-19 symptoms harbored SARS-CoV-2 for a couple of months and beyond. In some immunocompromised patients, the virus may not be cleared for a year. Four percent of COVID-19 patients in a trial on chronic COVID-19 infection at Stanford continued to shed viral RNA in feces seven months after diagnosis. However, Batra’s study illustrates that a larger number of patients take longer to clear the virus than previously realized.
“Persistent RNA shedding would mean that there still is a reservoir of virus somewhere in the body,” says Michael VanElzakker, a neuroscientist affiliated with Massachusetts General Hospital, Harvard Medical School and Tufts University. Such reservoirs are thought to allow the virus to persist over a long period of time and could trigger the immune system to act aberrantly, perhaps causing long COVID.
“Some patients, for variety of reasons, are not able to clear this reservoir, or their immune system reacts in some abnormal way that results in these persistent symptoms that have come to be termed as long COVID,” says Batra.
Still, many scientists don’t think there is sufficient evidence yet to link the persistence of viral RNA to long COVID.
The list of human tissues where SARS-CoV-2 hides long after the initial infection is growing. Studies have identified the virus, or genetic material from it, in the intestines of patients four months after initial infection, and inside the lung of a deceased donor more than a hundred days after recovery from COVID-19. One study that’s not yet peer reviewed also detected the virus in the appendix and breast tissues 175 and 462 days, respectively, after coronavirus infections. And research from the U.S. National Institutes of Health that’s also not yet peer reviewed detected SARS-CoV-2 RNA persisting at low levels across multiple tissues for more than seven months, even when it was undetectable in blood.
“It is not surprising to find viruses encountered during the lifetime” surviving in human tissues, says Kei Sato, a virologist at the University of Tokyo. Indeed, Sato’s work has shown that humans frequently accumulate viruses such as Epstein-Barr virus, varicella zoster virus (which causes chicken pox), and many herpes viruses in dormant forms. These persisting viruses are typically present at low levels, so only extensive genetic sequencing can identify them.
This highlights how complicated it is to prove or disprove the association between persisting SARS-CoV-2 and long COVID. Shingles, for example, occurs decades after a chickenpox infection, when the latent virus gets reactivated during immune stress.
Likewise, lingering SARS-CoV-2 could cause long-term health problems. Henrich thinks when the virus is seeded in deep tissues, it potentially causes the immune system to shift into a dysregulated inflammatory state. Such a state is “probably evidence that the virus is capable of persisting, and maybe getting down into sort of an uneasy truce with the body,” says VanElzakker.
Still, associating any lingering virus with long COVID will require extensive studies. “We still don’t know enough to make strong conclusions about any of the current proposed mechanisms, but research is actively underway to answer those questions,” says Geng.
Clearing up persistent virus might cure long COVID
Both Geng and Henrich’s groups have reported preliminary case studies that show an improvement in long COVID symptoms after patients were treated with Pfizer’s COVID-19 oral antiviral Paxlovid. Paxlovid stops the virus from replicating, which is why some experts think it can clear any lingering virus. But both authors urge caution before assuming that Paxlovid will be safe, effective, or sufficient and thereby a reliable cure for long COVID.
“There are some interesting hypotheses about how Paxlovid may be useful in the treatment of long COVID, but we’d need further investigation and clinical trials before coming to any conclusions,” says Geng.
The U.S. Food and Drug Administration has warned against off-label uses of Paxlovid, which is not approved for long COVID treatment. The agency has given Paxlovid an emergency use authorization to treat mild to moderate COVID-19 in those who are at risk of developing severe disease, twice daily for five days soon after a positive test.
“It would be important to consider the optimal duration of treatment [of Paxlovid] to ensure long-term and sustained results,” says Geng.
President Joe Biden has directed the secretary of Health and Human Services to create a national action plan on long COVID, and the NIH has launched a multi-year study called RECOVER to understand, prevent, and treat long-term health effects related to COVID-19.
In the meantime, vaccines not only continue to protect against severe disease, but evidence is also emerging that they can prevent many long COVID symptoms. One new study compared 1.5 million unvaccinated COVID-19 patients to 25,225 vaccinated patients with breakthrough infections, and it found that vaccines significantly reduced the risk of developing long COVID symptoms 28 days after an infection. The protective effect of vaccination got even larger at 90 days post-infection.
“Although a majority of people do not develop long COVID, it’s certainly a risk, and COVID doesn’t stop after the first 10 days of becoming infected,” says Henrich. “For those who don’t take COVID seriously, it can be life changing.”
No suspected cases of monkeypox in B.C., CDC says – Global News
The BC Centre for Disease Control has confirmed there are no suspected cases of monkeypox in the province.
“Public health interviewed two individuals but upon investigation, it was determined that they were not considered contacts of cases as they had not been exposed,” the BCCDC said in a statement.
“No suspect cases or contacts of monkeypox are under investigation in B.C. at this time.”
Canada’s chief public health officer said earlier Friday there are now just under two dozen cases of monkeypox in Canada and there were some suspected cases in B.C.
Dr. Theresa Tam said Friday that “people under investigation by local authorities are following up in Quebec but then in British Columbia as well.”
“A communication has gone out to regional health authorities and medical microbiologists about monkeypox with information on symptoms, laboratory testing and diagnosis, infection control precautions, treatment and notification/reporting requirements,” the BCCDC said in a statement. “Clinicians are asked to notify their regional health authority and local microbiologist about any possible cases.”
Canada’s top doctor discusses vaccine strategies for monkeypox
Monkeypox is a zoonotic infectious disease that results in occasional human infections usually associated with exposure to infected animals or contaminated materials, according to the Public Health Agency of Canada (PHAC).
“Limited cases have been identified in other regions in the past, including the United Kingdom, United States, Israel and Singapore, but never before in Canada,” the agency said.
While human-to-human spread of monkeypox is uncommon, close contact with an infected individual through bodily fluids, lesions on skin like blisters and/or respiratory droplets can transmit the virus, PHAC said.
Sharing clothing, bedding or common items that have been contaminated with the infected person’s fluids or sores can also spread the virus.
On Wednesday, the U.S. confirmed its first case of monkeypox this year in a man who recently travelled to Canada.
Health officials in European countries where monkeypox cases have been found this month said the majority of the cases were men who have sex with men.
Monkeypox: What is it and is it a cause for concern?
Tam said Friday there could be more cases announced in the days ahead as tests are still being conducted.
“There are samples under processing at the National Microbiology Lab as we speak, so we might expect to hear more confirmations in the upcoming hours and days,” Tam told reporters during a news conference on Friday.
—with files from Saba Aziz
© 2022 Global News, a division of Corus Entertainment Inc.
Russian vodka, caviar and diamonds on new Canadian sanctions list
Smaller telcos could feel the pinch after Ottawa prohibits use of Huawei’s 4G gear
Canada considering smallpox vaccine for monkeypox cases, says Dr. Theresa Tam
Silver investment demand jumped 12% in 2019
Europe kicks off vaccination programs | All media content | DW | 27.12.2020 – Deutsche Welle
Global Media Markets, 2015-2020, 2020-2025F, 2030F – TV and Radio Broadcasting, Film and Music, Information Services, Web Content, Search Portals And Social Media, Print Media, & Cable – GlobeNewswire
Media21 hours ago
Taylor Swift is now a Doctor
Health23 hours ago
What’s the Science Behind Why we Often Ignore Good Advice?
Media21 hours ago
Social media post at DP Todd sparks police investigation – My PG Now
Tech15 hours ago
Experience Parallel Search Capabilities on the HUAWEI Mate Xs 2 with Petal Search – Canada NewsWire
Art21 hours ago
Local artists selected for Art in Public Places program – Stony Plain Reporter
News21 hours ago
Abortion accessibility in Canada: The Catholic hospital conflict – CTV News
News20 hours ago
Canada bans Chinese tech giant Huawei from 5G network – CBC News
Tech18 hours ago
Apple's new iPhone privacy ad shows your data on the auction block – AdAge.com