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

Elvira D’Angelo, 92, waits to receive her COVID-19 vaccination shot at a clinic in Montreal, Sunday, March 7, 2021, as the COVID-19 pandemic continues in Canada and around the world. THE CANADIAN PRESS/Graham Hughes
110 new cases of COVID-19 in Interior Health

Provincial health officers announced 1,005 new cases throughout B.C.

Kristian Camero and Jessica Wood, seen here, co-own The Black Cauldron with Stephen Barton. The new Nelson restaurant opened earlier this month while indoor dining is restricted by the province. Photo: Tyler Harper
A restaurant opens in Nelson, and no one is allowed inside

The Black Cauldron opened while indoor dining is restricted in B.C.

These two city-owned houses on Railway Avenue in the Railtown district will be sold. Photo: Bill Metcalfe
City of Nelson will sell two derelict houses in Railtown

Purchasers will be responsible for demolition and slope stability issues

First-year Selkirk College student Terra-Mae Box is one of many talented writers who will read their work at the Black Bear Review’s annual (virtual) launch on April 22. Photo: Submitted
A grant from the province will fund the installation of lighting and electrical in the stage at Cottonwood Park and the construction of a washroom. Photo: Bill Metcalfe
City of Nelson receives grant for washroom and electrical at Cottonwood Falls Park stage

Grant will also fund concession stand and parking improvements

Rainbow trouts thrashing with life as they’re about to be transferred to the largest lake of their lives, even though it’s pretty small. These rainbows have a blue tinge because they matched the blue of their hatchery pen, but soon they’ll take on the green-browns of their new home at Lookout Lake. (Zoe Ducklow/News Staff)
VIDEO: B.C. lake stocked with hatchery trout to delight of a seniors fishing club

The Cherish Trout Scouts made plans to come back fishing soon

Cannabis bought in British Columbia (Ashley Wadhwani/Black Press Media)
Is it time to start thinking about greener ways to package cannabis?

Packaging suppliers are still figuring eco-friendly and affordable packaging options that fit the mandates of Cannabis Regulations

Royal Inland Hospital in Kamloops. (Dave Eagles/Kamloops This Week file photo)
RCMP intercept vehicle fleeing with infant taken from Kamloops hospital

The baby was at the hospital receiving life-saving care

Vancouver Police Const. Deepak Sood is under review by the Independent Investigations Office of B.C. after making comments to a harm reduction advocate Sunday, April 11. (Screen grab)
VIDEO: Vancouver officer convicted of uttering threats under watchdog review again

Const. Deepak Sood was recorded Sunday saying ‘I’ll smack you’ and ‘go back to selling drugs’ to a harm reduction advocate

Provincial health officer Dr. Bonnie Henry prepares a daily update on the coronavirus pandemic, April 21, 2020. (B.C. Government)
B.C.’s COVID-19 infection rate persists, 1,005 new cases Friday

Hospitalization up to 425, six more virus-related deaths

Premier John Horgan receives a dose of the AstraZeneca COVID-19 vaccine at the pharmacy in James Bay Thrifty’s Foods in Victoria, B.C., on Friday, April 16, 2021. THE CANADIAN PRESS/Chad Hipolito
B.C. Premier John Horgan gets AstraZeneca shot, encourages others

27% of residents in B.C. have now been vaccinated against COVID-19

The Nautical Dog Cafe at Skaha marina is getting its patio ready in hopes Mother Nature will provide where provincial restrictions have taken away indoor dining. (Facebook)
‘A lot of instability’: B.C. restaurants in layoff limbo

As COVID-19 cases stay high, restaurants in British Columbia are closed to indoor dining

Prime Minister Justin Trudeau looks on as Deputy Prime Minister and Finance Minister Chrystia Freeland responds to a question during a news conference on Parliament Hill in Ottawa, Tuesday, Aug. 18, 2020. THE CANADIAN PRESS/Adrian Wyld
Expectations high as Trudeau Liberals get ready to unveil first pandemic budget

The Liberals will look to thread an economic needle with Monday’s budget

Since April 4, 38 flights with COVID-19 cases have departed from Vancouver International Airport, while 23 arrived. (Phil McLachlan/Capital News)
Vancouver the largest source of domestic flights with COVID-19 cases: data

This month alone, 38 flights with COVID-19 cases have departed from Vancouver International Airport, while 23 arrived

Most Read