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What do we know about breakthrough COVID cases? Experts break down the science – Powell River Peak

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As COVID-19 cases rise through parts of the country, experts expect the number of infections among fully vaccinated people will increase with them. But that doesn’t mean the vaccines have stopped working.

Cases among fully vaccinated individuals — dubbed breakthrough infections if they occur at least two weeks following a second dose — are rare, experts say, even against the more transmissible Delta variant. And the chance a fully vaccinated person would get seriously ill or die following a COVID-19 infection is even less likely, they add.

“To date, the vaccines are doing exactly what we would expect them to be doing,” said Dr. Isaac Bogoch, an infectious disease physician with the University of Toronto. 

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“They reduce people’s risk of getting the infection, they significantly reduce the risk of people getting very sick and landing in hospital, and there’s also good growing data demonstrating that vaccines reduce the degree to which someone is contagious.”

So what do we know about breakthrough infections? The Canadian Press asked Bogoch and other health experts to break down the science:

HOW OFTEN ARE BREAKTHROUGH CASES HAPPENING? 

Data from Public Health Ontario showed breakthrough cases accounted for less than one per cent of all COVID-19 infections in the province from Dec.14, 2020 to Aug. 7, 2021. 

But as the proportion of vaccinated Canadians grows, so too will the number of vaccinated people exposed to the circulating Delta variant. And experts say we’ll likely see more breakthrough cases.

Those without shots are still significantly more vulnerable, though: Ontario public health data found unvaccinated individuals were about eight times more likely to contract COVID-19 in the past 30 days. Recent cases in British Columbia showed a 10-times higher rate of infection among unvaccinated people and a 17-times higher hospitalization rate.

Dr. Sumon Chakrabarti, an infectious disease physician in Mississauga, Ont., said that while Delta is a problem, the vaccines are still offering excellent protection.

“There’s just so much more of Delta right now so we’re seeing people who are getting COVID after they have the vaccine — but they’re almost uniformly getting mild disease,” he said. “As time goes on we’ll see more (breakthroughs) because we’re looking for them.

“But you have to compare it to the vast number of fully vaccinated people being exposed to COVID and not (catching it).”

A U.K. study from July suggested vaccine effectiveness dipped against Delta compared to the Alpha variant, offering between 67 and 88 per cent protection against infection. But effectiveness against death and severe disease has remained high.

WHO IS MORE LIKELY TO SUFFER SERIOUS BREAKTHROUGH INFECTIONS?

Though it doesn’t happen often, some fully vaccinated people have either required hospitalization or intensive care or died following a breakthrough infection.

Bogoch said emerging worldwide data suggests those who suffer serious breakthrough outcomes are likely to have other risk factors for severe disease.

“This is usually older or frail adults or immunocompromised individuals,” he said. “And these are people that won’t mount the same degree of an immune response to vaccination compared to younger cohorts.”

Since those segments of the population were also among the first prioritized for vaccination when Canada’s rollout began in December, some experts say waning immunity may be at play for certain groups.

A pre-print study from immunologists at McMaster University suggests those in long-term care could soon need a booster shot to amplify their protection.

“In the general population, it is not believed that we have reached that waning immunity,” said Dawn Bowdish, a co-author of the pre-print study which is currently under review. “In long-term care and in the vulnerable, yes, they’re reaching waning immunity, but they never have immune responses that last as long.”

Chakrabarti said most studies on immune longevity look at antibody levels over time. But while antibodies decrease, T-cell responses linger much longer to continue to help fight off severe infection.

“Antibodies are like a brick wall. They’re strong but with enough force you can knock them down,” he said. “But the kind of long-term immunity you have with your T-cells, that’s like a concrete wall. That’s not something that easily drops.”

CAN BREAKTHROUGH INFECTIONS LEAD TO FURTHER TRANSMISSION?

Recent data from the United Kingdom showed that some fully vaccinated COVID-19 patients had similar viral loads to unvaccinated people who contracted the virus. While that would seem to suggest vaccinated people are just as contagious, experts say that’s not the case.

Bowdish said further studies have indicated viral load drops much quicker in fully vaccinated people compared to those unvaccinated: “So you might have one day of being infectious versus five,” she explained.

“Right now we’re seeing Delta is just as contagious as chicken pox in unvaccinated people,” Bowdish said. “In vaccinated people, it’s probably closer to influenza…. So a fully vaccinated person, there’s still potential to transmit, but it will be a lot less.”

Bowdish added that the amount of viral load someone carries around doesn’t necessarily translate to how infectious the person is. 

She pointed out that studies during the first wave, before Delta emerged, suggested children carried high loads of virus but weren’t as contagious as adults. She said the presence of symptoms and the behaviour of the host — are they sneezing and surrounded by people?— impact transmission more than viral load itself. 

Chakrabarti added viral load doesn’t always indicate the presence of live virus, and since vaccinated people likely won’t have symptoms, they also likely won’t become super-spreaders. 

HOW DO WE STOP BREAKTHROUGH CASES?

Some experts believe the COVID-19 virus will become endemic, with small, seasonal waves continuing to pass through predominantly unprotected populations. That means it will be hard to stop breakthrough infections entirely.

Bogoch said the best way to halt spread among both vaccinated and unvaccinated groups is to continue with added layers of protection, including mask-wearing and limits on indoor gatherings, to “stop infections in the community.”

“Right now, we have to vaccinate plus have other mitigation efforts in place simultaneously,” he said. “We’ll get out of this pandemic. We’re just not there yet.”

This report by The Canadian Press was first published Aug. 26, 2021.

Melissa Couto Zuber, The Canadian Press

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Supervised consumption sites urgently needed, says study – Sudbury.com

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A study in the Canadian Medical Association Journal (CMAJ) said the opioid drug crisis has reached such a critical level that a public safety response is urgently required and that includes the need for expanded supervised consumption sites.

The report was published by the medical journal Monday and was authored by Shaleesa Ledlie, David N. Juurlink, Mina Tadrous, Muhammad Mamdani, J. Michael Paterson and Tara Gomes; physicians and scientists associated with the University of Toronto, Sunnybrook Research Institute and the Li Ka Shing Knowledge Institute at St. Michael’s Hospital.

“The drug toxicity crisis continues to accelerate across Canada, with rapid increases in opioid-related harms following the onset of the COVID-19 pandemic,” the authors wrote. “We sought to describe trends in the burden of opioid-related deaths across Canada throughout the pandemic, comparing these trends by province or territory, age and sex.”

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The study determined that across Canada, the burden of premature opioid-related deaths doubled between 2019 and 2021, representing more than one-quarter of deaths among younger adults. The disproportionate loss of life in this demographic group highlights the critical need for targeted prevention efforts, said the study.

The researchers found that the death rate increased significantly as fentanyl was introduced to the mix of street drugs that individuals were using, in some cases, unknowingly.  

The authors said this demonstrates the need for consumption sites, not only as overwatch as people with addictions consume their drugs, but also to make an effort to identify the substances and inform those people beforehand. 

“The increased detection of fentanyl in opioid-related deaths in Canada highlights the need for expansion of harm-reduction programs, including improved access to drug-checking services, supervised consumption sites, and treatment for substance use disorders,” the authors wrote. 

The study said a more intense public safety response is needed. 

“Given the rapidly evolving nature of the drug toxicity crisis, a public safety response is urgently required and may include continued funding of safer opioid supply programs that were expanded beginning in March 2020, improved flexibility in take-home doses of opioid agonist treatment, and enhanced training for health care workers, harm reduction workers, and people who use drugs on appropriate responses to opioid toxicities involving polysubstance use.

In conclusion, the authors wrote that during the height of the COVID pandemic in 2020 and 2021, the burden of premature death from accidental opioid toxicities in Canada dramatically increased, especially in Alberta, Saskatchewan, and Manitoba. 

“In 2021, more than 70 per cent of opioid-related deaths occurred among males and about 30 per cent occurred among people aged 30–39 years, representing one in every four deaths in this age group. The disproportionate rates of opioid-related deaths observed in these demographic groups highlight the critical need for the expansion of targeted harm reduction–based policies and programs across Canada,” said the study.

The full text of the report can be found online here.

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Business Plan Approved for Cancer Centre at NRGH – My Cowichan Valley Now

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A business plan for a new BC Cancer Centre at Nanaimo Regional General Hospital has been approved by the province. 

 

Health Minister Adrian Dix  says the state-of-the-art cancer facility will benefit patients in Nanaimo and the surrounding region through the latest medical technology.
 

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The facility will have 12 exam rooms, four consultation rooms and space for medical physicists and radiation therapists, medical imaging and radiation treatment of cancer patients. 

 

The procurement process is underway, and construction is expected to begin in 2025 and be complete in 2028. 

 

Upgrades to NRGH have also been approved, such as a new single-storey addition to the ambulatory care building and expanded pharmacy. 

 

Dix says Nanaimo’s population is growing rapidly and aging, and stronger health services in the region, so people get the health care they need closer to home. 

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Outdated cancer screening guidelines jeopardizing early detection, doctors say – Powell River Peak

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A group of doctors say Canadian cancer screening guidelines set by a national task force are out-of-date and putting people at risk because their cancers aren’t detected early enough. 

“I’m faced with treating too many patients dying of prostate cancer on a daily basis due to delayed diagnosis,” Dr. Fred Saad, a urological oncologist and director of prostate cancer research at the Montreal Cancer Institute, said at a news conference in Ottawa on Monday. 

The Canadian Task Force on Preventive Health Care, established by the Public Health Agency of Canada, sets clinical guidelines to help family doctors and nurse practitioners decide whether and when to recommend screening and other prevention and early detection health-care measures to their patients.

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Its members include primary-care physicians and nurse practitioners, as well as specialists, a spokesperson for the task force said in an email Monday. 

But Saad and other doctors associated with the Coalition for Responsible Healthcare Guidelines, which organized the news conference, said the task force’s screening guidelines for breast, prostate, lung and cervical cancer are largely based on older research and conflict with the opinions of specialists in those areas. 

For example, the task force recommends against wide use of the prostate specific antigen test, commonly known as a PSA test, for men who haven’t already had prostate cancer. Saad called that advice, which dates back to 2014, “outdated” and “overly simplistic.” 

The task force’s recommendation is based on the harms of getting false positive results that lead to unnecessary biopsies and treatment, he said. 

But that reasoning falsely assumes that everyone who gets a positive PSA test will automatically get a biopsy, Saad said. 

“We are way beyond the era of every abnormal screening test leading to a biopsy and every biopsy leading to treatment,” he said, noting that MRIs can be used to avoid some biopsies.

“Canadian men deserve (to) have the right to decide what is important to them, and family physicians need to stop being confused by recommendations that go against logic and evidence.”

Dr. Martin Yaffe, co-director of the Imaging Research Program at the Ontario Institute for Cancer Research, raised similar concerns about the task force’s breast cancer screening guideline, which doesn’t endorse mammograms for women younger than 50.

That’s despite the fact that the U.S. task force says women 40 and older may decide to get one after discussing the risks and benefits with their primary-care provider. 

The Canadian task force is due to update its guidance on breast cancer screening in the coming months, but Yaffe said he’s still concerned.

“The task force leadership demonstrates a strong bias against earlier detection of disease,” he said.

Like Saad, Yaffe believes it puts too much emphasis on the potential harm of false positive results.

“It’s very hard for us and for patients to balance this idea of being called back and being anxious transiently for a few days while things are sorted out, compared to the chance of having cancer go undetected and you end up either dying from it or being treated for very advanced disease.”

But Dr. Eddy Lang, a member of the task force, said the harms of false positives should not be underestimated. 

“We’ve certainly recommended in favour of screening when the benefits clearly outweigh the harms,” said Lang, who is an emergency physician and a professor at the University of Calgary’s medical school. 

“But we’re cautious and balanced and want to make sure that we consider all perspectives.” 

For example, some men get prostate cancer that doesn’t progress, Lang said, but if they undergo treatments they face risks including possible urinary incontinence and erectile dysfunction. 

Lang also said the task force monitors research “all the time for important studies that will change our recommendations.” 

“And if one of them comes along, we prioritize the updating of that particular guideline,” he said. 

The Canadian Cancer Society pulled its endorsement from the task force’s website in December 2022, saying it hadn’t acted quickly enough to review and update its breast cancer screening guidelines to consider including women between 40 and 50. 

“(The Canadian Cancer Society) believes there is an obligation to ensure guidelines are keeping pace with the changing environment and new research findings to ensure people in Canada are supported with preventative health care,” it said in an emailed statement Monday evening. 

Some provinces have implemented more proactive early detection programs, including screening for breast cancer at younger ages, using human papillomavirus (HPV) testing to screen for cervical cancer and implementing CT scanning to screen for lung cancer, doctors with the Coalition for Responsible Healthcare Guidelines said. 

But that leads to “piecemeal” screening systems and unequal access across the country, said Dr. Shushiela Appavoo, a radiologist with the University of Alberta.

Plus, many primary-care providers rely on the national task force guidelines in their discussions with patients, she said. 

“The strongest association … with a woman actually going for her breast cancer screen is whether or not her doctor recommends it to her. So if her doctor is not recommending it to her, it doesn’t matter what the provincial guideline allows,” Appavoo said. 

In addition to updating its guideline for breast cancer screening this spring, the task force is due to review its guidelines for cervical cancer screening in 2025 and for lung cancer and prostate cancer screening in 2026, according to its website.

This report by The Canadian Press was first published April 16, 2024.

Canadian Press health coverage receives support through a partnership with the Canadian Medical Association. CP is solely responsible for this content.

Nicole Ireland, The Canadian Press

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