Dr. Howard Njoo, Deputy Chief Public Health Officer, provides an update on the COVID-19 pandemic in Ottawa on Friday, Jan. 8, 2021. THE CANADIAN PRESS/Sean Kilpatrick

Dr. Howard Njoo, Deputy Chief Public Health Officer, provides an update on the COVID-19 pandemic in Ottawa on Friday, Jan. 8, 2021. THE CANADIAN PRESS/Sean Kilpatrick

Canadian officials seek to convince a skeptical public of vaccine safety

Canada, which has used about 500,000 doses so far, has not had any blood clot reports from the AstraZeneca vaccine

Canada’s deputy chief public health officer wouldn’t hesitate to roll up his sleeve if the Oxford-AstraZeneca vaccine were offered to him tomorrow, he said this week.

Dr. Howard Njoo, along with chief public health officer Dr. Theresa Tam, has become one of the most prominent voices on COVID-19 in Canada.

For the last week, both have spent most of their time trying to explain why a vaccine that may have caused deadly blood clots is still considered to be safe, at least for some.

Their defenses of the vaccine highlight one of the most serious problems facing Canada’s immunization program to date, and medical experts are trying desperately to explain to Canadians that the twists and turns around vaccination advice and authorizations are not a sign of looming danger.

“I think the fundamental challenge with this pandemic is that science and evidence and knowledge is always evolving and is emerging fast,” said Tam during a March 31 Facebook Live event on vaccines.

“So we have to act fast to adapt and evolve the guidance when new evidence warrants it.”

With the AstraZeneca shot, the pace of new information is enough to give someone whiplash.

In the 36 days since Health Canada gave it the green light, the National Advisory Committee on Immunization has changed its age recommendations for the vaccine three times — first saying there wasn’t enough evidence it was effective for seniors, then two weeks later saying there was. Finally, on March 29, NACI said there was a need to pause its use on people under 55 because there had been more cases in Europe where people developed blood clots after receiving the shot.

The European Medicines Agency said as of March 22, they had reports of 62 cases and 14 deaths. In Germany, as of March 29, there had been 31 cases and nine deaths. More than five million doses have been injected in Europe.

Canada, which has used about 500,000 doses so far, has not had any blood clot reports, nor did any emerge during the vaccine’s trials.

Dr. Menaka Pai, a clinical hematologist at Hamilton’s McMaster University, said the blood clot situation is so unusual it didn’t even have a name before now.

“I have to say, this is the most rapid discovery that I’ve ever seen,” she said. “I’m pretty stunned.”

The disorder is now called Vaccine-Induced Prothrombotic Immune Thrombocytopenia or VIPIT. Pai describes it as a very rare immune response where the antibodies the body makes following the vaccine begin targeting platelets.

Platelets are blood cells that normally form clots to help stop bleeding, such as when you cut yourself.

Pai said the antibody is activating the platelets all over the body and making them sticky, creating many little clots all over the place. Those clots can block blood flow and cause serious symptoms, including death.

If it’s caught, the symptom is treatable with drugs that thin the blood, smoothing out the clots. Symptoms appear four to 20 days after vaccination, and may include severe and persistent headaches, seizures, blurred vision, chest pain, shortness of breath, severe swelling, pain or a colour change in an arm or leg.

Pai said there is no understanding yet of why it is happening and vaccines have never caused such an effect before. She said it’s not likely connected to the fact COVID-19 also causes a lot of blood clots, because the source of those clots are very different.

As many as one in five patients hospitalized with COVID-19 will develop a blood clot. For patients in intensive care the risk is as high as one in three.

So why not stop the vaccine for everyone if it’s causing a potentially-fatal blood clot in some patients?

The doctors say that’s where the risk-benefit analysis is crucial. Yes, there is a risk from the vaccine, but what is that risk compared to the risk of what could happen if you get COVID-19?

“How they looked at it was really the vaccine is safe and effective overall,” said Tam. “But these rare serious events we’re seeing being reported in younger age groups and for these young age groups, the serious outcomes from COVID-19 is lower than for the older age groups. So hence, they went ahead and recommended that, for now, put a pause for everyone’s safety sake, just put a pause until we get more data.”

The majority of blood clot cases reported in Europe are in women under the age of 55 but Pai said that could be because more women under 55 got vaccinated with it. Europe initially targeted AstraZeneca at health care workers, a field dominated by women.

Most of Canada’s first doses went to people in their early 60s but the vaccine only started being used here in mid-March so the data could be limited.

But in the United Kingdom, where very few blood clots have been seen, and where the vaccine has been used for three months, the majority of early recipients were seniors. Pai said that is contributing to the belief VIPIT is much less likely in seniors.

Pai said she agrees with pausing the vaccine for younger people while more analysis is done to understand the actual risk. But she says she also is increasingly worried that people see this is as a reason to not trust the science.

“It really should not shake our confidence in vaccines,” she said. “I think if anything it should reassure all of us that, wow, you know vaccine safety and surveillance systems in Canada really work and our government is being thoughtful and you know we can trust the system. I hope it does that instead of the opposite.”

Coronavirus

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

Six people are said to have escaped injury and are currently receiving assistance after an early Sunday morning fire in Central Saanich displaced them. (Central Saanich Fire Department/Twitter)
Six people escape early Sunday morning fire in Central Saanich unharmed

Cause of the fire on Galbraith Close remains under investigation

Metchosin ecologist Andy MacKinnon is raising alarm bells for arbutus trees, as many are falling victim to a fungus called leaf blights. The leaves and branches of the trees are turning brown or black and then dropping off, eventually killing them. (Dawn Gibson/News Staff)
Vancouver Island arbutus trees fighting for survival against parasites

Many trees weakened, turning black or brown and dying, says local ecologist

Applied theatre researcher Dennis Gupa wearing a traditional Filipino malong at a local beach in Victoria. (Credit: John Threlfall)
UVic researcher uses theatre to empower marginalized voices, fight climate change

Dennis Gupa looks to create new modes of expression, knowledge sharing

Sooke resident Lesa Cro started up a new pet waste removal business. Cro goes to yards in the region, removes all of the waste and then composts it, so that it doesn’t go into landfills. (Dawn Gibson/News Staff)
New pet poop-scooping business picks up in Sooke

Poop No More service taking the ‘dirty work’ out of lawn cleaning

Vancouver resident Beryl Pye was witness to a “concerning,” spontaneous dance party that spread throughout social groups at Kitsilano Beach on April 16. (Screen grab/Beryl Pye)
VIDEO: Dance party erupts at Vancouver’s Kitsilano Beach to the dismay of onlookers

‘It was a complete disregard for current COVID-19 public health orders,’ says Vancouver resident Beryl Pye

Each spring, the Okanagan Fest-of-Ale is held in Penticton. This year, as a result of the COVID-19 pandemic, the festival will not be held. However, beer is still available. How much do you know about this beverage? (pxfuel.com)
QUIZ: How much do you really know about beer?

Put your knowledge to the test with this short quiz

Lord Tweedsmuir’s Tremmel States-Jones jumps a player and the goal line to score a touchdown against the Kelowna Owls in 2019. The face of high school football, along with a majority of other high school sports, could significantly change if a new governance proposal is passed at the B.C. School Sports AGM May 1. (Malin Jordan)
Power struggle: New governance model proposed for B.C. high school sports

Most commissions are against the new model, but B.C. School Sports (BCSS) and its board is in favour

Russ Ball (left) and some of the team show off the specimen after they were able to remove it Friday. Photo supplied
Courtenay fossil hunter finds ancient turtle on local river

The specimen will now make its home at the Royal BC Museum

Pall Bearers carrying the coffin of the Duke of Edinburgh, followed by the Prince of Wales, left and Princess Anne, right, into St George’s Chapel for his funeral, at Windsor Castle, in Windsor, England, Saturday April 17, 2021. (Danny Lawson/Pool via AP)
Trudeau announces $200K donation to Duke of Edinburgh award as Prince Philip laid to rest

A tribute to the late prince’s ‘remarkable life and his selfless service,’ the Prime Minister said Saturday

B.C. homeowners are being urged to take steps to prepare for the possibility of a flood by moving equipment and other assets to higher ground. (J.R. Rardon)
‘Entire province faces risk’: B.C. citizens urged to prepare for above-average spring flooding

Larger-than-normal melting snowpack poses a threat to the province as warmer weather touches down

Vancouver-based Doubleview Gold Corp. is developing claims in an area north of Telegraph Creek that occupies an important place in Tahltan oral histories, said Chad Norman Day, president of the Tahltan Central Government. (THE CANADIAN PRESS/HO)
B.C. Indigenous nation opposes mineral exploration in culturally sensitive area

There’s “no way” the Tahltan would ever support a mine there, says Chad Norman Day, president of its central government

Stz’uminus Elder George Harris, Ladysmith Mayor Aaron Stone, and Stz’uminus Chief Roxanne Harris opened the ceremony. (Cole Schisler photo)
Symbolic red dresses rehung along B.C. highway after vandals tore them down

Leaders from Stz’uminus First Nation and the Town of Ladysmith hung new dresses on Sat. April 17

A Western toadlet crosses the centre line of Elk View Road in Chilliwack on Aug. 26, 2010. A tunnel underneath the road has since been installed to help them migrate cross the road. Saturday, April 24 is Save the Frogs Day. (Jenna Hauck/ Progress File)
Unofficial holidays: Here’s what people are celebrating for the week of April 18 to 24

Save the Frogs Day, Love Your Thighs Day and Scream Day are all coming up this week

Most Read