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Health Canada has approved the Pfizer/BioNTech drug as the Trudeau government and provinces get organized to deliver it to Canadians, but there are more vaccine candidates in the works

A nurse at the Royal Cornwall Hospital in Truro, England, prepares to administer COVID-19 vaccinations. Britain has approved the Pfizer-BioNTech vaccine, as has Canada.Hugh Hastings/Getty Images

At a time when cases of COVID-19 are surging toward ever higher numbers in Canada, it’s hard to imagine more welcome news than Health Canada’s approval of its first vaccine to prevent the virus from spreading. But as public-health experts are quick to point out, it is not vaccines but vaccination that will ultimately stop the pandemic. With a rollout of vaccines under way in Britain and expected to begin in Canada in December, here is what experts are saying about what we know, what we don’t and what we can expect in the months ahead.


Overview: Status of vaccines so far


How effective are the COVID-19 vaccines Canada has arranged to buy?

Canada was among the countries that moved quickly to ink deals for some of the leading vaccine candidates, based on recommendations from a federally appointed task force. So far, it looks like those bets are paying off. Canada has a lock on 20 million doses of vaccine produced jointly by Pfizer Inc. and Germany’s BioNTech. That vaccine was the first to pass through a Phase 3 clinical trial with data showing it to be 95-per-cent effective, and the first to be approved by Health Canada, a decision announced on Dec. 8.

That vaccine’s impressive score is based on just 170 people among the 45,000 participants in the trial who got COVID-19 within one month of getting their first shot. Only 5 per cent of those 170 cases occurred in people who received the vaccine. The rest received a placebo instead.

The good news was further bolstered by equally strong interim results from a vaccine produced by Moderna in Cambridge, Mass. Moderna’s vaccine is also destined for Canada with an order of up to 56 million doses. The two orders combined are enough to vaccinate every Canadian with the required two doses.

Both Pfizer and Moderna’s drugs rely on a new technology. Unlike traditional vaccines, which work by delivering a weakened virus or viral proteins to help train the body’s immune system, these vaccines consist of tiny particles that carry genetic instructions in the form of RNA, which the body takes up and uses to generate copies of viral proteins.

Gary Kobinger, a Laval University researcher who developed the vaccine for Ebola, said he is happy that Canada has also purchased five other COVID-19 vaccines, including those based on more proven technologies. There’s a good chance that most of them will work now that two have been shown to perform well, he said.

“I think it looks good for a lot other vaccines to see some level of protection,” he said, in part because, despite their differences, the vaccines are all based on the same idea: presenting or coaxing the body to manufacture copies of the coronavirus spike protein – the knobby protrusion that surrounds the virus and allows it to infect cells.

On Nov. 23, the U.K.-based pharmaceutical company AstraZeneca announced that its vaccine candidate, developed in partnership with Oxford University, is also showing good efficacy based on interim results from a multinational Phase 3 trial. The two-dose vaccine was only 62-per-cent effective in one arm of the trial, but when the amount of vaccine delivered in the first dose was halved, it became 90-per-cent effective. Scientists are now awaiting the complete results from the trial in order to understand why the lower dosage may have performed so much better.

A significant difference between the AstraZeneca vaccine and those produced by Pfizer and Moderna is that AstraZeneca’s product can be shipped and stored at standard refrigerator temperatures.


Which COVID-19 vaccines have been approved in Canada?

Watch: Ivan Semeniuk explains how Canadian authorities are assessing COVID-19 vaccine candidates while trials are under way, but it’s likely high-risk people will be prioritized for receiving any vaccine first.

The Globe and Mail

So far, only the Pfizer drug has been authorized for Canadian use, soon after the U.S. Food and Drug Administration released a briefing document of the clinical-trial evidence related to it. Pfizer and Moderna have previously said in news releases that their vaccines produced no serious adverse effects.

Since October, Pfizer, Moderna and AstraZeneca’s drugs have been undergoing regulatory review in Canada through a “rolling submission,” which allows evaluation by regulators to begin before all the data are gathered. While this approach is intended to advance the process more quickly, the COVID-19 vaccines will still have to meet the same safety standards that apply to all vaccines that Health Canada approves, said Supriya Sharma, the department’s chief medical adviser. “This is what our vaccine reviewers do day in and day out,” Dr. Sharma said. “They make these assessments of the data around benefits, risks and uncertainties and determine whether or not something should be authorized.”

Even when approved, the data from clinical trials involving tens of thousands of participants will not be enough to detect safety issues that could be significant but rare. These may become apparent only after millions of people have been given the vaccine. This is why monitoring of the vaccines will continue long after the approval process, as it would for any vaccine or drug, Dr. Sharma said.

Another mystery is whether the vaccines can actually stop the spread of COVID-19.

Since the coronavirus can be transmitted by people before they show symptoms of the disease, including those who never show symptoms at all, it will be difficult to learn from clinical trials alone whether the vaccines reduce transmission, or simply turn more people into asymptomatic spreaders. The upshot is that until more is known, masks and physical distancing are likely to remain recommended precautions.

Finally, public-health agencies have no way to know yet how long a vaccine will confer immunity to COVID-19. “It’s early days, but I’m optimistic,” said Tal Zaks, chief medical officer for Moderna. “Immunity should hold for many months … but we will continue to follow [clinical trial] participants for two years and monitor the degree to which they’re protected.”


How will the COVID-19 vaccines be distributed?

A DHL worker loads dry ice into 'Envirotainers' at a facility for the shipment of vaccines and medical supplies in Chicago.DHL/Handout via REUTERS

While many details are still being worked out, one thing is clear: Previous vaccination programs will pale in comparison to what is about to be attempted. “This will be one of the most complicated and important mass health interventions in our lifetime,” said Kumanan Wilson, a senior scientist at the Ottawa Hospital Research Institute.

Public Service and Procurement Canada, which handles the multiple orders, could begin receiving the first batches of vaccines early next year. Once they arrive, the vaccines will fall under the purview of the Public Health Agency of Canada and will be distributed to each province and territory. Discussions around how this will happen are now under way between governments.

Pfizer and Moderna have said they expect to produce tens of millions of doses by the end of this year and hundreds of millions for the global market in 2021.

There are physical complications to transporting and storing the vaccines, particularly RNA vaccines, which are not stable at room temperature. This creates the need for a “cold chain” that allows the vaccines to be shipped to their many destination points without losing their potency. Pfizer’s vaccine must be stored at -70 C, which requires specialized equipment, while Moderna has said commercial freezers will do for its vaccine. Acuitas Therapeutics in Vancouver licenses its technology to make the tiny lipid nanoparticles that contain the RNA in the Pfizer vaccine. President and CEO Thomas Madden said the two vaccines are similar enough that Pfizer’s will likely turn out to be just as viable as Moderna’s under the same storage conditions.

Dr. Kobinger said people can feel encouraged by the fact the latest Ebola epidemic was declared over this week in the Democratic Republic of Congo, thanks in part to a vaccine that has similar cold-chain requirements to Pfizer’s COVID-19 vaccine. “It’s much easier to have cold storage in Canada, even at -70, than it is in the middle of the tropical forest in Africa,” he said.

Another hurdle will simply be keeping track of who has been vaccinated and who hasn’t – something that will be all the more challenging because multiple vaccines will be available and most will require two doses. Differences between provincial systems for vaccination record keeping will further complicate the task.


Who will get the COVID-19 vaccines first in Canada?

A nurse welcomes a man to a Montreal COVID-19 testing clinic on Nov. 9.Paul Chiasson/The Canadian Press/The Canadian Press

Public-health officials are increasingly optimistic that COVID-19 vaccines will be available to most Canadians as early as next summer. Between now and then, the number of available doses will be limited and some population groups are expected to be prioritized.

Those groups have already been identified in recommendations by an independent panel appointed by the federal government.

The high-priority groups include those who are at elevated risk of severe illness and death from COVID-19, including seniors and those with health complications. They also include health care workers and others who are part of the pandemic response, as well as providers of essential services and people who are working in settings where physical distancing and other preventive measures are challenging or who live in places where access to health care is reduced, including Indigenous communities.

Caroline Quach, an infectious-diseases specialist and microbiologist at the University of Montreal who chairs the committee, said that more details on how those priority groups should be ordered could be made public as early as the week of Nov. 23. However, provincial and territorial governments will ultimately have to decide who fits into the groups and in what order vaccinations will be offered.

Whether someone is placed in a priority group or not, the federal government has made clear that a vaccine will eventually be made available to everyone who wants one at no cost.

A potentially more serious question is how many will choose not to be vaccinated. This will have an impact on efforts to control the pandemic and on the return to normal life.

Ève Dubé, a professor of medical anthropology at Laval University, has been conducting weekly surveys on attitudes toward vaccination in Quebec since March. She said that while about 75 per cent of those surveyed during the first wave of the pandemic said they were willing to be vaccinated, that number fell by 15 to 20 per cent by the fall.

Good public communication will be essential to the success of the vaccination effort, she said. Her message to health agencies: “Be transparent. Be clear about what we know, what we don’t know and what we’re doing to fill the gaps.”



BY THE NUMBERS

The next curve: Three stages of a vaccine rollout

Like other countries, Canada will face limited supplies of COVID-19 vaccines at first and higher-risk groups will be given priority ahead of the general population.​ While different priority groups have not yet been ranked, this chart shows a plausible plan for a vaccine rollout.

DOSES AVAILABLE

*Dotted line indicates uncertainty about

duration of vaccine immunity

Max.

Trials

only

TIME

LIMITED DOSES AVAILABLE

Constrained supply

 

Highly targeted administration required to achieve coverage in priority populations

Example population

Health care professionals and first responders

 

People with high-risk conditions

 

Older adults, including those in long-term care homes

DOSES AVAILABLE

Max.

Trials

only

TIME

LARGE NUMBER OF DOSES AVAILABLE

Likely sufficient supply meet demand

 

Supply increases access

 

Broad administration network required

Example population

Non-health-care essential workers

 

People working in settings where prevention is difficult

 

Communities with reduced access to health care

 

People most likely to transmit to high-risk groups

DOSES AVAILABLE

Max.

Trials

only

TIME

CONTINUED VACCINATION, SHIFT TO ROUTINE

STRATEGY

Likely excess supply

 

Broad administration network for increased access

Example population

All others who did not have access in previous phases

THE GLOBE AND MAIL, SOURCE: CDC; NACI

Like other countries, Canada will face limited supplies of COVID-19 vaccines at first and higher-risk groups will be given priority ahead of the general population.​ While different priority groups have not yet been ranked, this chart shows a plausible plan for a vaccine rollout.

DOSES AVAILABLE

*Dotted line indicates uncertainty about duration of vaccine immunity

Max.

Trials

only

TIME

LIMITED DOSES AVAILABLE

Constrained supply

 

Highly targeted administration required to achieve coverage in priority populations

Example population

Health care professionals and first responders

 

People with high-risk conditions

 

Older adults, including those in long-term care homes

DOSES AVAILABLE

Max.

Trials

only

TIME

LARGE NUMBER OF DOSES AVAILABLE

Likely sufficient supply meet demand

 

Supply increases access

 

Broad administration network required

Example population

Non-health-care essential workers

 

People working in settings where prevention is difficult

 

Communities with reduced access to health care

 

People most likely to transmit to high-risk groups

DOSES AVAILABLE

Max.

Trials

only

TIME

CONTINUED VACCINATION, SHIFT TO ROUTINE STRATEGY

Likely excess supply

 

Broad administration network for increased access

Example population

All others who did not have access in previous phases

THE GLOBE AND MAIL, SOURCE: CDC; NACI

Like other countries, Canada will face limited supplies of COVID-19 vaccines at first and higher-risk groups will be given priority ahead of the general population.​ While different priority groups have not yet been ranked, this chart shows a plausible plan for a vaccine rollout.

DOSES AVAILABLE AT DIFFERENT STAGES

Max.

LIMITED DOSES AVAILABLE

LARGE NUMBER OF DOSES AVAILABLE*

CONTINUED VACCINATION, SHIFT TO ROUTINE

STRATEGY*

TIME

*Dotted line indicates uncertainty about duration of vaccine immunity

Trials

only

Likely sufficient supply meet demand

 

Supply increases access

 

Broad administration network required

Constrained supply

 

Highly targeted administration required to achieve coverage in priority populations

Likely excess supply

 

Broad administration network for increased access

Example population

Example population

Example population

Health care professionals and first responders

 

People with high-risk conditions

 

Older adults, including those in long-term care homes

All others who did not have access in previous phases

Non-health-care essential workers

 

People working in settings where prevention is difficult

 

Communities with reduced access to health care

 

People most likely to transmit to high-risk groups

THE GLOBE AND MAIL, SOURCE: CDC; NACI


How RNA vaccines work

The COVID-19 pandemic has led to the debut of RNA vaccines, which are designed to harness the body’s own cells to imitate a viral infection and train the immune system to attack the coronavirus. RNA vaccines, which are faster to produce, have emerged as front-runners, but other types of vaccines that may ultimately be less costly or provide other advantages are also being developed.

RNA VACCINE

Vaccine delivers RNA sequence inside a protective envelope

RNA enters host cell and provides instructions to make coronavirus spike protein

RNA

Host cell

Spike

protein

RNA enters host cell and provides instructions to make coronavirus spike protein

Antibody

Presence of spike protein stimulates production of antibodies and other responses

The immune system is now primed to recognize the coronavirus and generate antibodies that prevent the virus from attaching to host cells via the ACE2 receptor.

COVID-19

virion

ACE2

receptor

MURAT YÜKSELIR AND IVAN SEMENIUK /

THE GLOBE AND MAIL

The COVID-19 pandemic has led to the debut of RNA vaccines, which are designed to harness the body’s own cells to imitate a viral infection and train the immune system to attack the coronavirus. RNA vaccines, which are faster to produce, have emerged as front-runners, but other types of vaccines that may ultimately be less costly or provide other advantages are also being developed.

RNA VACCINE

Vaccine delivers RNA sequence inside a protective envelope

RNA enters host cell and provides instructions to make coronavirus spike protein

RNA

Host cell

Spike

protein

RNA enters host cell and provides instructions to make coronavirus spike protein

Antibody

Presence of spike protein stimulates production of antibodies and other responses

The immune system is now primed to recognize the coronavirus and generate antibodies that prevent the virus from attaching to host cells via the ACE2 receptor.

COVID-19

virion

ACE2

receptor

MURAT YÜKSELIR AND IVAN SEMENIUK /

THE GLOBE AND MAIL

The COVID-19 pandemic has led to the debut of RNA vaccines, which are designed to harness the body’s own cells to imitate a viral infection and train the immune system to attack the coronavirus. RNA vaccines, which are faster to produce, have emerged as front-runners, but other types of vaccines that may ultimately be less costly or provide other advantages are also being developed.

RNA VACCINE

Vaccine delivers RNA sequence inside a protective envelope

RNA enters host cell and provides instructions to make coronavirus spike protein

RNA

Host cell

Spike

protein

RNA enters host cell and provides instructions to make coronavirus spike protein

Antibody

Presence of spike protein stimulates production of antibodies and other responses

The immune system is now primed to recognize the coronavirus and generate antibodies that prevent the virus from attaching to host cells via the ACE2 receptor.

COVID-19

virion

ACE2

receptor

MURAT YÜKSELIR AND IVAN SEMENIUK / THE GLOBE AND MAIL


How the AstraZeneca/Oxford vaccine works

16/16

14/14

11/11

The Oxford University and AstraZeneca Covid-19

vaccine can prevent up to 90 per cent of people

contracting coronavirus when it is administered as

a half dose followed by a full dose

at least one month apart

Spike

protein

Spike protein:

Gene is cut from

Sars-CoV-2 genome

Virus

genome

Gene: Inserted into DNA

of adenovirus which acts

as vector in vaccine

Gene

Adenovirus:

Unable to

cause disease

Vaccine: Induces spike

protein antigen – triggers

antibody immune response

Antibodies

Human immune

system: Produces

antibodies against

spike proteins

Vaccine: Can be

stored in refrigerator

at 2-8°C. Two doses

of vaccine are

required

graphic news, SOURCE: Reuters; Oxford

Vaccine Trial; University of Oxford

16/16

14/14

11/11

The Oxford University and AstraZeneca Covid-19 vaccine

can prevent up to 90 per cent of people contracting

coronavirus when it is administered as a half dose

followed by a full dose at least one month apart

Spike

protein

Spike protein:

Gene is cut from

Sars-CoV-2 genome

Virus

genome

Gene: Inserted into DNA

of adenovirus which acts

as vector in vaccine

Gene

Adenovirus:

Unable to

cause disease

Vaccine: Induces spike

protein antigen – triggers

antibody immune response

Antibodies

Human immune

system: Produces

antibodies against

spike proteins

Vaccine: Can be

stored in refrigerator

at 2-8°C. Two doses

of vaccine are

required

graphic news, SOURCE: Reuters; Oxford Vaccine Trial;

University of Oxford

18/18

16/16

13/13

The Oxford University and AstraZeneca Covid-19 vaccine can prevent

up to 90 per cent of people contracting coronavirus when it is administered

as a half dose followed by a full dose at least one month apart

Spike protein

Adenovirus:

Unable to

cause disease

Gene

Virus genome

Spike protein:

Gene is cut from

Sars-CoV-2 genome

Gene: Inserted into DNA

of adenovirus which acts

as vector in vaccine

Antibodies

Vaccine: Induces spike

protein antigen – triggers

antibody immune response

Human immune

system: Produces

antibodies against

spike proteins

Vaccine: Can be

stored in refrigerator

at 2-8°C. Two doses

of vaccine are required

graphic news, SOURCE: Reuters; Oxford Vaccine Trial; University of Oxford


With a report from Kelly Grant

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