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

Nav Canada will not be closing the tower at West Kootenay Regional Airport. Photo: Betsy Kline
Nav Canada tower to remain open at West Kootenay Regional Airport

The organization was considering closing the tower

Dresses hang outside Nelson city hall as part of the REDress Project by Métis artist Jaime Black. Photo: Bill Metcalfe
Nelson’s REDress Project exhibit vandalized

The REDress Project brings attention to missing and murdered Indigenous women

A woman wears a protective face covering to help prevent the spread of COVID-19 as she walks past the emergency entrance of Vancouver General Hospital in Vancouver, B.C., Friday, April 9, 2021. THE CANADIAN PRESS/Jonathan Hayward
54 more cases of COVID-19 in Interior Health

Thirty-two people in the region are in hospital with the virus, 11 of them in intensive care

Dr. Katherine Oldfield is a naturopathic physician, mother, and active member of the Nelson-West Kootenay chapter of Citizens’ Climate Lobby. Photo: Submitted
COLUMN: Restore our Earth, restore our health

Katherine Oldfield marks Earth Day by writing about the priorities we need to have

Canadian Prime Minister Justin Trudeau and United States President Joe Biden smile as they say farewell following a virtual joint statement in Ottawa, Tuesday, February 23, 2021. THE CANADIAN PRESS/Adrian Wyld
Trudeau pledges to cut emissions by 40% to 45% by 2030, short of U.S. goal

Trudeau announced target during a virtual climate summit convened by U.S. President Joe Biden

Journal de Montreal is seen in Montreal, on Thursday, April 22, 2021. The daily newspaper uses a file picture of Prime Minister Justin Trudeau dressed in traditional Indian clothing during his trip to India to illustrate a story on the Indian variant of the coronavirus. Paul Chiasson/The Canadian Press
Montreal newspaper blasted for front-page photo of Trudeau in India

Trudeau is wearing traditional Indian clothes and holding his hands together in prayer beside a caption that reads, ‘The Indian variant has arrived’

Nanaimo RCMP say a man was injured while pouring gunpowder on a backyard fire in Harewood on Wednesday, April 21. (File photo)
Nanaimo man hospitalized after pouring gunpowder onto backyard fire

RCMP investigating explosion in Harewood also came across a still for making alcohol on property

Provincial health officer Dr. Bonnie Henry arrives for briefing on the COVID-19 situation, B.C. legislature, Oct. 26, 2020 (B.C. government)
B.C. sees 1,006 COVID-19 cases Thursday, ‘alarming’ 502 in hospital

Vaccine bookings for people aged 60 and older set to start

Shannon Zirnhelt, from left, her son Lockie, 3, Julia Zirnhelt, 13, and Ella Krus, 13, co-founders of Third Planet Crusade are featured in a music video set to air on Earth Day, April 22, 2021. (Monica Lamb-Yorski photo - Williams Lake Tribune)
B.C.-made music video launched in time for Earth Day 2021

Singer songwriter Shannon Zirnhelt worked with Third Planet Crusade on the project in the Cariboo

Ambulance crews have been busy with a record number of emergency overdose calls this Wednesday, April 21. (BC Emergency Health Services)
B.C. paramedics responded to a record 138 overdose calls in a single day

Wednesday’s calls included 48 in the Vancouver Coastal Health region and 51 in Fraser Health

B.C. Health Minister Adrian Dix and Premier John Horgan describe vaccine rollout at the legislature, March 29, 2021. (B.C. government)
B.C. COVID-19 hotspots targeted as AstraZeneca vaccine runs low

17,000 appointments booked the first day for people aged 40 and up

A nurse loads a syringe with a vaccine for injection at the Victoria Clipper Terminal. THE CANADIAN PRESS/Chuck Stoody
B.C.’s COVID-19 vaccine rollout not enough to bring back normal life by fall: report

Only 51% of the population will be protected under B.C.’s current rollout, SFU professors say more vaccinations are needed to achieve herd immunity

Most Read