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Why Canada's decision to delay 2nd doses of COVID-19 vaccines may not work for everyone – CBC.ca

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New research from two small pre-print studies suggests delaying second doses of COVID-19 vaccines by up to four months may not be the best approach for some older Canadians.

The research comes as some experts are also questioning whether Canada’s vaccination advisers, who recommended the delay, can keep up with rapidly evolving science during the pandemic.

Prior to the pandemic, the National Advisory Committee on Immunization (NACI), which has provided guidance to the federal government on vaccinations since 1964, met just three times a year to discuss issues related to vaccines for influenza, mumps, measles and other viruses.

But a year after the pandemic was declared, with new data emerging daily, NACI has been thrust into the spotlight and forced to evaluate new vaccines for a novel virus faster than ever before.

“NACI’s committees are basically made up of volunteers, many with heavy daily responsibilities during the pandemic,” said Dr. David Naylor, co-chair of Canada’s COVID-19 Immunity Task Force.

“There’s no precedent for NACI to operate at this pace, and everyone is adapting on the fly.”

NACI has met nine times since Canada approved its first COVID-19 vaccine on Dec. 10, but it has plans to ramp up in the coming months with another 13 meetings scheduled between now and the end of June.

Guido Armellin, 86, receives the COVID-19 vaccine during a clinic at a church in Toronto on March 17. A team was on-site administering the Pfizer-BioNTech vaccine to parishioners as part of a community outreach program to get seniors vaccinated at their place of worship. (Evan Mitsui/CBC)

The committee has previously overturned its initial guidance against immunocompromised individuals and pregnant women receiving COVID-19 vaccinations, as well as a controversial decision against the AstraZeneca-Oxford vaccine for those over 65.

Delay could leave cancer patients less protected, U.K. study suggests

Perhaps one of NACI’s most impactful recommendations on Canada’s vaccine rollout was the decision to delay second doses beyond manufacturing guidelines by up to four months, but emerging research signals it may not be the best approach for vulnerable Canadians.

A new pre-print study, which has not yet been peer reviewed, analyzed 151 older cancer patients and compared their immune response with 54 healthy adults after receiving the first and second doses of the Pfizer-BioNTech COVID-19 vaccine in the U.K.

The researchers concluded that delaying second doses to between eight and 12 weeks for most cancer patients left them “wholly or partially unprotected” and had implications on their health and the potential emergence of coronavirus variants. 

WATCH | Delaying some 2nd COVID-19 vaccine doses challenged by new data:

New early data suggests that Canada’s recommendation of delaying the second dose of COVID-19 vaccines to up to four months may not be effective in some older, more vulnerable patients, causing the vaccine advisory committee to re-examine its guidance. 2:36

“Our data advocates that bringing forward the second dose of the vaccine for patients who have cancer may benefit them,” said Leticia Monin-Aldama, lead author of the study and a researcher at the Francis Crick Institute in London.

“And that perhaps a sort of one-size-fits-all approach may not be ideal when delivering these vaccines to the population.”

NACI advocated for that universal approach to delay second doses by up to four months for all Canadians — the longest interval recommended by a country so far — based on limited real-world evidence and the reality of Canada’s vaccine supply.

The decision was also informed by findings from Dr. Danuta Skowronski, epidemiology lead at the British Columbia Centre for Disease Control (BCCDC), who determined that one dose of the vaccine was actually more effective than clinical trials had initially shown.

NACI said if second doses were stretched to four months across the country, close to 80 per cent of Canadians over the age of 16 could get at least one shot by the end of June.

But Canada’s chief science adviser, Mona Nemer, has said the decision to delay second doses amounted to a “population level experiment” and advised against the delay in older Canadians on CTV’s Power Play this week, citing a lack of data to back up the decision.

Darryl Falzarano, a research scientist with the Vaccine and Infectious Disease Organization (VIDO) lab in Saskatoon, is also against the decision to increase the time between doses and said there is a growing body of research that suggests it’s not the safest approach for immunocompromised and older adults.

“The initial data look like delaying the dose of the mRNA vaccines would still provide reasonable protection to the population from severe or moderate disease, and so vaccinating more people was looked at as the greater good,” he said.

“Now, in certain populations — older people, people with comorbidities and cancers — likely delayed boosting for them is sub-optimal and possibly will lead to revised recommendations for those groups.”

Darryl Falzarano, a research scientist with the Vaccine and Infectious Disease Organization lab in Saskatoon, is opposed to increasing the time between doses and says there is a growing body of research that suggests it’s not the safest approach for immunocompromised and older adults. (Debra Marshall)

B.C. study analyzed long-term care residents

A second pre-print study released this week from researchers in British Columbia, which has also not been peer reviewed, cast further doubt on the dose delay for seniors and found that their immune response may not be as strong as in younger, healthier people.

The study analyzed antibody levels in a dozen long-term care residents in Vancouver a month after receiving their first dose of a COVID-19 vaccine, compared with 22 younger health-care workers — 18 of whom had not previously been infected by COVID-19 and four who had.

“The level of antibodies in older residents was fourfold lower, so significantly decreased,” said Dr. Marc Romney, a clinical associate professor at the University of British Columbia in Vancouver and one of the authors of the study. “The function of those antibodies in older people was also compromised.”

Romney said antibodies are just part of the picture, and he also plans to look at the immune system’s full response in future research. But he said the fact that antibodies in the elderly didn’t neutralize the virus as well as in the younger health-care workers suggests the dose delay may need to be revised for them.

“There is emerging evidence that demonstrates that there are some populations that will probably not fare as well and have the same degree of protection following single doses of a vaccine,” said Dr. Isaac Bogoch, an infectious diseases physician and member of Ontario’s COVID-19 Vaccine Distribution Task Force.

“These are groups you would want to shorten the time between dose one and two.”

WATCH | The science behind delaying the 2nd dose of COVID-19 vaccines:

Federal government scientists have put their support behind delayed second doses of COVID-19 vaccines — which several provinces were already doing — and ongoing research shows some of the benefits of the adapted strategy. 2:04

‘This isn’t a regular vaccine’

The speed with which NACI members are able to make these decisions has come under fire.

Falzarano said NACI is typically used to working under a “slow-moving” vaccine regulatory process where vaccines can take up to a decade to go from research to rollout.

“Their job is to review vaccines, but their experience is reviewing them under a much different scenario,” he said.

“They are normally looking at a full data set when they have to make decisions. They would normally make very conservative decisions, and now, they find themselves in a much different scenario than what they’re used to — and I think that’s highly challenging for them.”

Visitors to a mass vaccination clinic in Toronto on Tuesday fill in paperwork as they wait in line. The National Advisory Committee on Immunization initially recommended against giving the AstraZeneca-Oxford vaccine to seniors, but that guidance changed on March 16 after it reviewed data. (Frank Gunn/The Canadian Press)

NACI’s decision to recommend against the AstraZeneca-Oxford shot for seniors on March 1 came despite emerging evidence from around the world demonstrating its ability to prevent severe COVID-19 in older adults.

But that guidance changed on March 16 after more real-world data on the vaccine’s effectiveness was reviewed by NACI, and CBC News broke the story revealing documents on the federal government’s plans to allow those 65 and older to receive it.

Alyson Kelvin, an assistant professor at Dalhousie University and a virologist at the IWK Health Centre and the Canadian Centre for Vaccinology, all in Halifax, said NACI should include more experts in emerging viruses and vaccine development to help navigate the research in the pandemic.

“This isn’t a regular vaccine that’s gone through the typical workflow for vaccine approval and vaccine development because it’s an emerging virus,” said Kelvin, who is also evaluating Canadian vaccines at the VIDO lab in Saskatoon.

“You need somebody who understands that dynamic, instead of what we would normally depend on for our medicines or vaccines.”

Dr. Caroline Quach-Thanh, who chairs NACI, responded to criticism during a news conference on March 16, saying that as new evidence emerged on the efficacy of the AstraZeneca-Oxford vaccine in older adults, NACI was “busy with other files” that delayed its guidance.

“The committee is very busy, obviously, meeting weekly to discuss the emerging data on these important topics,” said Matthew Tunis, executive secretary to the committee.

“So there’s always inevitably going to be a bit of a lag between when a committee deliberates and when the advice is made public.”

Decisions take time, NACI chair says

Quach-Thanh responded to further questions about the delay in revising recommendations on CBC’s Power and Politics on Wednesday, noting that NACI isn’t equipped to review new evidence one day and make recommendations the next.

“It’s not possible, we can’t be that reactive,” she said. “I don’t think any advisory committee can be that reactive because it would mean that every time something changes, you move the needle one way or the next.

Dr. Caroline Quach-Thanh, who chairs the National Advisory Committee on Immunization, says NACI is currently re-examining its guidance based on new research, and new guidelines on the timing of second doses for seniors and the immunocompromised could come as early as next week. (Skype)

“Then it just means that you’re changing your recommendation every other day. So you need to gather that base of evidence before you change something.”

But even after NACI has finalized its recommendations, Quach-Thanh said, it takes an entire week to translate and upload them to the Public Health Agency of Canada’s website — precious time in a pandemic where new data emerges daily.

Quach-Thanh said the committee is currently re-examining its guidance based on new research, and new guidelines on the timing of second doses for seniors and the immunocompromised could come as early as next week. But Skowronski, with the BCCDC, said it’s too early to make that call definitively.

“This is a kind of a signal that we might want to follow, it’s of interest, but we cannot change or make policy on the basis of this sort of small study,” she said.

“It may come to pass that we will want to adjust depending upon how far we have come in achieving that goal of getting at least one dose into these individuals at highest risk.”

Skowronski defended the decision to delay second doses by up to four months in Canada and stressed that the benefits of vaccinating more vulnerable groups with an initial shot outweigh the risks of delaying a second.

“My preoccupation is in at least getting a first dose into those at high risk of severe complications, and we’ve not achieved that yet,” she said, adding that age was by far the biggest risk factor for severe outcomes from COVID-19.

“That’s job one. Let’s get that job one done, and then let’s debate the timing of the second dose.”

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Canada will not restrict AstraZeneca COVID-19 vaccine, says benefits outweigh risk

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OTTAWA (Reuters) – Canada‘s health ministry said on Wednesday it would not restrict use of AstraZeneca Plc’s COVID-19 vaccine after a review showed the benefits outweighed the very rare risk of blood clots.

A separate advisory council had earlier recommended Canada stop offering the vaccine to people under 55. The panel is now reviewing that advice, the health ministry said in a statement.

Denmark on Wednesday became the first country to stop using the vaccine altogether over a potential link to the rare blood clots. Other nations have imposed limits on its use.

But Health Canada, the federal health ministry, said in a statement that a review of data from Europe, Britain and AstraZeneca had not identified specific risk factors.

“Therefore, Health Canada is not restricting the use of the vaccine in any specific populations at this time … The potential risk of these events is very rare, and the benefits of the vaccine in protecting against COVID-19 outweigh its potential risks,” it said.

Canada on Tuesday said it had recorded its first case of blood clotting with low platelets after someone received the AstraZeneca shot. The patient in question, a woman from Quebec, is recovering. (Graphic on vaccines: https://tmsnrt.rs/3tUM8ta)

COVID-19 cases are surging in Canada with the country reporting a near-record number of new cases recently. (Graphic on cases: https://tmsnrt.rs/34pvUyi)

 

(Reporting by David Ljunggren in Ottawa and Allison Martell in Toronto; Editing by Lisa Shumaker)

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Factbox-Some countries limit AstraZeneca vaccine use, US pauses J&J shot

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(Reuters) -Some countries are restricting use of the AstraZeneca COVID-19 vaccine to certain age groups or suspending use after European and British regulators confirmed possible links to rare blood clots.

Denmark became the first country to stop using the vaccine altogether, as it said results of investigations showed “real and serious side-effects”.

Johnson & Johnson’s single-shot vaccine has also been hit by concerns over blood clots, with European regulators reviewing such cases and U.S. federal health agencies recommending pausing its use for a few days. J&J noted no clear causal relationship had been established between the clots and its vaccine.

The developments pose a risk to vaccination plans in Europe.

Regulators have said the benefits of the AstraZeneca shot outweigh risks.

Anglo-Swedish drugmaker AstraZeneca said it was working with regulators to list the possible brain blood clots as “an extremely rare potential side effect” on the vaccines labels.

As of April 4, the European Medicines Agency had received reports of 169 cases of a rare brain blood clot known as cerebral venous sinus thrombosis (CVST), after 34 million doses had been administered in the European Economic Area. Most cases were in women under 60 years of age.

ASTRAZENECA VACCINE BEING USED, WITH OR WITHOUT RESTRICTIONS

AUSTRALIA

Said on April 8 it recommends people under 50 should get Pfizer’s COVID-19 vaccine in preference to AstraZeneca’s shot.

AUSTRIA

Has resumed use.

BRAZIL

Authorities said they would not limit use of the AstraZeneca vaccine, saying benefits outweigh risks.

BRITAIN

The Joint Committee on Vaccination and Immunisation has said an alternative to the vaccine should be given for people under 30 where possible, but people should continue to have a second shot if they have received a first dose.

BULGARIA

Resumed inoculations from March 19.

CYPRUS

Resumed inoculations on March 19.

CANADA

Authorities said in early April they would pause offering the vaccine to people under 55 and require a new analysis of the shot’s benefits and risks based on age and gender. On April 13, the country said it had recorded its first case of blood clotting with low platelets.

ESTONIA

Suspended use of the vaccine for people under 60 on April 7.

FRANCE

Approved resumption of the vaccine on March 19 but said it should be given only to people aged 55 and over. On April 9, recommended that recipients of a first dose of the AstraZeneca shot who are under 55 should receive a second dose with a messenger RNA vaccine.

FINLAND

Resumed using the AstraZeneca vaccine from March 29, but only for people aged 65 and over.

GEORGIA

Has limited use of the vaccine following the death of a nurse from anaphylactic shock, and vaccinations will continue only in full-fledged medical centres, Russian news agency TASS reported on March 19.

GERMANY

Sticking to its guidance from March 31 to limit use of the vaccine to those aged over 60. On April 1, Germany’s vaccine commission recommended people under 60 who have had a first shot of the vaccine should receive a different product for their second dose.

HUNGARY

Continuing the vaccine’s rollout.

ICELAND

Resumed use on March 25 after suspending it on March 11.

INDONESIA

Resumed using the vaccine on March 22 but warned against its use in people with a low blood platelet count.

IRELAND

On April 12, the country said it was restricting use of the vaccine to those over 60.

ITALY

Has recommended the vaccine be used only for people over 60, the country’s top health adviser said.

LATVIA

Announced it was restarting administering the shots from March 19.

LITHUANIA

Restarted use on March 19.

MEXICO

Drug regulator Cofepris said on April 7 it did not “at this time” plan to limit the vaccine’s use but was investigating the information raised by Britain.

NETHERLANDS

Limited use of the vaccine to people over 60, the Dutch government said on April 8.

NORTH MACEDONIA

Health minister said on March 31 the vaccine would be limited to people aged over 60 as a precautionary measure.

PHILIPPINES

Suspended use of the vaccine for people under 60 on April 8.

ROMANIA

Has resumed use of the vaccine after temporarily stopping vaccinating people with one batch of the vaccine on March 11.

SOUTH KOREA

Resumed use of the shot for people aged 30 or older on April 12. On April 7, it had suspended providing the AstraZeneca shot to people under 60.

SPAIN

From April 8, it was giving the vaccine only to people over 60.

SWEDEN

Resumed use of the vaccine on March 25 for people aged 65 and older.

THAILAND

Began use on March 15 after delaying rollout the week before.

COUNTRIES WHERE ASTRAZENECA VACCINE USE SUSPENDED

CAMEROON

Suspended administration of the vaccine it was scheduled to receive on March 20 as part of the global vaccines sharing scheme COVAX, the health ministry said.

DENMARK

In a world first, Denmark decided to stop using the AstraZeneca vaccine altogether after initially suspending use of the shot.

NORWAY

Authorities said on March 26 Norway would delay a decision on use of the vaccine, with a decision expected by April 15.

J&J VACCINE DELAYS AND RESTRICTIONS

UNITED STATES

On April 13, U.S. federal health agencies recommended pausing use of J&J’s COVID-19 vaccine for at least a few days after six women under the age of 50 developed rare blood clots after receiving the shot.

EUROPEAN UNION

The company said it would delay the rollout of the vaccine to Europe, after regulators said they were reviewing rare blood clots.

Widespread use in the EU had not yet started after the company began delivering the doses in the week beginning April 12. The European drug regulator recommended storing doses already received until its safety committee issues an expedited recommendation

SOUTH AFRICA

Suspended use of J&J’s vaccine on April 13.

(Reporting by Pushkala Aripaka, Yadarisa Shabong, Manas Mishra, Vishwadha Chander, Amruta Khandekar and Mrinalika Roy in Bengaluru; editing by Josephine Mason, Alison Williams, Timothy Heritage, Larry King, Barbara Lewis)

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Ontario hospitals may have to withhold care as COVID-19 fills ICUs

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By Allison Martell and Anna Mehler Paperny

TORONTO (Reuters) – Doctors in the Canadian province of Ontario may soon have to decide who can and cannot receive treatment in intensive care as the number of coronavirus infections sets records and patients are packed into hospitals still stretched from a December wave.

Canada‘s most populous province is canceling elective surgeries, admitting adults to a major children’s hospital and preparing field hospitals after the number of COVID-19 patients in ICUs jumped 31% to 612 in the week leading up to Sunday, according to data from the Ontario Hospital Association.

The sharp increase in Ontario hospital admissions is also straining supplies of tocilizumab, a drug often given to people seriously ill with COVID-19.

Hospital care is publicly funded in Canada, generally free at the point of care for residents. But new hospital beds have not kept pace with population growth, and shortages of staff and space often emerge during bad flu seasons.

Ontario’s hospitals fared relatively well during the first wave of the pandemic last year, in part because the province quickly canceled elective surgeries.

The College of Physicians and Surgeons of Ontario told doctors last Thursday that the province was considering “enacting the critical care triage protocol,” something that was not done during earlier waves of the virus. Triage protocols help doctors decide who to treat in a crisis.

“Everybody’s under extreme stress,” said Eddy Fan, an ICU doctor at Toronto’s University Health Network. He said no doctor wants to contemplate a triage protocol but there are only so many staff.

“There’s going to be a breaking point, a point at which we can’t fill those gaps any longer.”

In a statement, the health ministry said Ontario has not activated the protocol. A September draft suggested doctors could withhold life-sustaining care from patients with a less than 20% chance of surviving 12 months. A final version has not been made public.

Ontario’s Science Advisory Table had been forecasting the surge for months, said member and critical care physician Laveena Munshi. During a recent shift she wanted to call the son of a patient only to discover he was in an ICU across the street.

“The horror stories that we’re seeing in the hospital are like ones out of apocalyptic movies,” she said. “They’re not supposed to be the reality we’re seeing one year into a pandemic.”

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