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Scientists find signs of waning antibody immunity to COVID-19 over time in England – CBC.ca

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Antibodies against the novel coronavirus declined rapidly in the population in England during the summer, according to a preprint posted on Tuesday, suggesting protection after infection may not be long-lasting and raising the prospect of waning immunity in the community.

Scientists at Imperial College London have tracked antibody levels in the population in England following the first wave of COVID-19 infections in March and April.

Their study found that antibody prevalence fell by a quarter, from six per cent of the population around the end of June to just 4.4 per cent in September. That raises the prospect of decreasing population immunity ahead of a second wave of infections in recent weeks that has forced local lockdowns and restrictions.

Although immunity to the novel coronavirus is a complex and murky area, and may be assisted by T cells as well as B cells, which can stimulate the quick production of antibodies following re-exposure to the virus, the researchers said the experience of other coronaviruses suggested immunity might not be enduring.

“We can see the antibodies and we can see them declining and we know that antibodies on their own are quite protective,” Wendy Barclay, head of the Department of Infectious Disease at Imperial College London, told reporters.

“On the balance of evidence I would say, with what we know for other coronaviruses, it would look as if immunity declines away at the same rate as antibodies decline away, and that this is an indication of waning immunity at the population level.”

Those for whom COVID-19 was confirmed with a gold standard PCR test had a less pronounced decline in antibodies, compared to people who had been asymptomatic and unaware of their original infection.

There was no change in the levels of antibodies seen in health-care workers, possibly due to repeated exposure to the virus.

Vaccine may be more protective

The study, which has not yet been peer reviewed to flag flaws, backs up findings from similar surveys in Germany. The German researchers found the vast majority of people didn’t have COVID-19 antibodies, even in hotspots for the disease, and that antibodies might fade in those who do.

WATCH | The limits of pursuing herd immunity:

A group of international experts push back against the Great Barrington Declaration and its pursuit of COVID-19 herd immunity, calling it “a dangerous fallacy unsupported by scientific evidence.” 2:05

World Health Organization spokesman Tarik Jasarevic said that uncertainty over how long immunity would last, and the fact that most people had never had antibodies against the coronavirus in the first place, showed the need to break transmission chains.

“Acquiring this collective immunity just by letting the virus run through the population is not really an option,” he told a UN briefing in Geneva.

Imperial’s study was based on a survey of 365,000 randomly selected adults.

The rapid waning of antibodies did not necessarily have implications for the efficacy of vaccine candidates currently in clinical trials, Imperial’s Barclay said.

“A good vaccine may well be better than natural immunity,” she said.

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Alberta's COVID-19 testing positivity rate hits 'grim milestone' at more than 10 per cent – CBC.ca

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On a day that Alberta reported 18,243 active cases of COVID-19 and 15 additional deaths, the province also reported a record high test positivity rate.

The positivity rate climbed to 10.5 per cent, a “grim milestone and one that should concern us all,” Dr. Deena Hinshaw, Alberta’s chief medical officer of health, told a news conference Friday.

With almost 17,200 people tested, and one of every 10 testing positive, the total number of new cases in Alberta reached 1,828.

To date 590 people have died in Alberta. As of Friday there were a record 533 people in hospital, including 99 in intensive care.

“We are heading into the first weekend of December,” Hinshaw said. “In a difficult year, I know this last month may be the toughest for many. This virus can spread quickly from one to many.

“In a month usually marked by festive gatherings, we feel the restrictions more keenly. But I want to stress the seriousness of the rising case numbers that we’re seeing and how crucial it is that we reduce the spread and bend the curve back down.”

Here is how the active cases break down among the regions:

  • Edmonton zone: 8,578 cases
  • Calgary zone: 6,666 cases
  • Central zone: 1,251 cases
  • North zone: 1,012 cases
  • South zone: 630 cases
  • Unknown: 106 cases

7 deaths at care home in Edmonton’s Chinatown

The 15 deaths reported Friday included seven people linked to an outbreak at the Edmonton Chinatown Care Centre: four men in their 90s, a woman in her 90s, a man in his 80s and a man in his 100s.

Other deaths reported Friday:

  • A woman in her 70s linked to the outbreak at Clifton Manor in Calgary.
  • A man in his 80s linked to the outbreak at Capital Care Lynnwood in Edmonton.
  • A man in his 70s from the Edmonton zone.
  • Two men in their 60s from the Edmonton zone.
  • A man in his 50s from the Edmonton zone.
  • A woman in her 70s from the Central zone.
  • A woman in her 90s from the Calgary zone.

Contact tracing getting help

Dr. Verna Yiu, president and CEO of Alberta Health Services, told the news conference AHS is working to bolster its troubled contact-tracing system.

“As case numbers have increased exponentially in the past six weeks it has become more and more difficult for our teams to keep up with demand,” Yiu said.

“We are rapidly increasing our response to the unprecedented volume of COVID-19 cases in the province.”

WATCH | Alberta to ramp up contact tracing efforts:

A desperate shortfall of COVID-19 contact tracers is one of the staffing challenges plaguing Alberta, says AHS president and CEO Dr. Verna Yiu. 1:29

The province has more than 900 contact tracers in Alberta and is on track to double that number by the end of the year, Yiu said.

“This means that we will have 36 contact tracers per 100,000 people, which will be on par or better compared to other provinces.” 

Bending the curve

Albertans are now one week into the latest round of restrictions aimed at bending the curve of COVID-19 cases in the province.

Last Friday, Premier Jason Kenney ordered junior and senior high schools to close, barred indoor social gatherings and capped capacity for businesses.

Next week Albertans will find out what impact those measures are having on the virus, which is spreading faster in Alberta than anywhere else in the country.

It was the second set of restrictions issued by the premier in November.

Three weeks ago, Kenney suspended indoor group fitness programs, team sports and group performance activities, and reduced operating hours for restaurants, bars and pubs in cities.  

But the curve didn’t bend and the virus has continued to surge since, setting records almost daily as it tightens its grip on the province.

The province’s contact-tracing system is struggling against demand. Alberta’s government continues to resist calls to adopt the federal contact-notification app or order a province-wide mask law.

It is also continuing to spurn calls by physicians for a two-week lockdown, or “circuit-breaker,” to drop the effective reproduction number and allow contact tracing to catch up. 

WATCH | Alberta requests field hospitals from Ottawa:

The Alberta government is in talks with Ottawa and the Canadian Red Cross for help in setting up field hospitals, as the number of COVID-19 patients continues to surge. 2:42

This week, the province acknowledged it is preparing for the worst. Alberta has asked the federal government for two field hospitals, and the Red Cross for two more. 

Alberta hospitals are preparing to double-bunk critically ill patients, revamp operating and recovery rooms and reassign staff to treat an expected surge of COVID-19 patients destined for intensive care units.  

AHS has asked hospitals in Calgary to begin rationing oxygen.

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About 77 per cent of COVID-19 victims have at least one comorbidity, officials say – CTV Toronto

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CALGARY —
While the majority of patients who have died from COVID-19 have had at least one comorbidity, or chronic condition, Alberta’s top doctor says it doesn’t mean that when a compromised individual catches the disease they could die.

Dr. Deena Hinshaw, Alberta’s chief medical officer of health, said Thursday that Alberta has always provided details on “severe outcomes” of the virus, including any comorbidities the patients have had.

About two weeks ago, the province introduced more specific information about whether or not comorbidities existed in the deaths currently being reported on a daily basis.

Alberta Health said the additional information, which includes the official date of death, was being released because of requests from the public and the media about those deaths.

However, Hinshaw says just because someone has one of the chronic conditions listed, it does not definitively mean they will die if they contract COVID-19.

“The presence of any chronic condition is not a death sentence and should not be,” she said. “Whether or not an individual who passed away had a chronic condition or not does not mean that that death was any less tragic.”

She also said Alberta has a risk assessment tool designed to help those with chronic conditions to understand their own risk.

“That’s a tool that we have updated over time as more information has become available – both through our own data in Alberta, as well as publications around the world,” she said.

Tom McMillan, assistant director of communications for Alberta Health, tells CTV News that Alberta has the “most in-depth and transparent” reporting of cases in the entire country.

“No other province shares as comprehensive and detailed data as we post online,” he said, adding Alberta Health is constantly looking for ways to provide additional data.

“We were the first province in Canada to offer a comprehensive online dashboard and were also the first to release ongoing data on severe outcomes, cases by age group and gender and other case characteristics.

“We have committed to providing Albertans with as timely and detailed information as possible while still protecting patient confidentiality.”

calgary, alberta health, comorbidity, covid 19, co

All three of the Albertans in their 20s who have died from COVID-19 had comorbidities, but the province has not released any more specific information due to privacy concerns.

Hinshaw also said that comorbidities do “disproportionately impact” those individuals, but every Albertan needs to do their part and follow all health rules to prevent the spread of COVID-19.

“It is up to every single one of us – whether or not we have a chronic condition – to be a part of the solution, and to be a part of protecting everyone in our society.”

Provincial data shows about 77 per cent of Alberta’s 575 deaths due to the disease have had at least one comorbidity.

calgary, alberta health, comorbidity, covid 19, co

(Source/Alberta Health Services)

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COVID-19 update for Dec. 4: B.C. records 711 new cases, 11 more deaths | Fraser Health introduces online form for contact tracing – Vancouver Sun

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Article content continued

Henry has expanded bans on high-intensity fitness classes like spin and hot yoga, to include all yoga and activities like tai chi and stretching.

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She has also ruled out all adult sports and most fitness activities; including beer-league hockey and ultimate. This came a day after reporting that an old-timers team from the Interior Health region had travelled to Alberta and come back infected. This led to dozens of cases among family and workmates and has caused an outbreak in at least one long-term care facility.

Henry said activities like tennis, swimming and golf were OK.

There were 694 cases of COVID-19 reported between noon Wednesday and noon Thursday, and 12 deaths. Henry said there were 9,103 active cases of the disease in B.C., of which 325 were in hospital and 80 in intensive care. The death tally is now 481.

Henry said a COVID-19 vaccine would be available to select British Columbians on Jan. 1, and would be widely available by the end of 2021.

12 a.m. – B.C. government bans all adult team sports

British Columbians are now prohibited from participating in adult team sports as the province tightens its COVID-19 restrictions.

The updated order covers all adult sports, whether they are played indoor or outdoors, including including basketball, cheerleading, combat sports, floor hockey, floor ringette, road hockey, ice hockey, ringette, netball, skating, soccer, curling, volleyball, indoor bowling, lawn bowling, lacrosse, hockey, ultimate, rugby, football, baseball, softball.

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