What to know about Canada’s new vaccine
AstraZeneca shot the third to be made available in Canada
Canada has a new COVID-19 vaccine at its disposal — one that relies on different technology than the other two doses that have been approved for use in this country.
The federal regulator announced Friday it has authorized the vaccine created in a collaboration between AstraZeneca and Oxford University. At the same time, the regulator also approved the version made by the Serum Institute of India, known by the name Covishield.
The federal government has already procured 20 million doses of the vaccine, and now says it has procured an additional two million doses from India, with the first shipment to arrive within weeks.
The AstraZeneca/Oxford vaccine has had a more winding journey to authorization than the previous two vaccines, with the European regulator at one point saying there wasn’t enough evidence to show it was effective in seniors. South African officials have also raised questions about its usefulness against the variant that emerged in their country.
But the approval of this shot is significant, experts say, because of the edge it has in terms of the speed at which it can be manufactured and the ease with which it can be shipped around the country.
“The transportability is really important — it offers more options, and more flexible vaccination planning at a health unit level,” Dr. Lynora Saxinger, an infectious diseases specialist at the University of Alberta, said in an email.
Federal officials also reiterated Friday that it will be just one weapon in their public health arsenal.
“The idea is to have a suite of vaccines that are available,” said Dr. Supriya Sharma, a senior medical adviser with Health Canada. “I think Canada is hungry for vaccines; we’re putting more on the buffet table to be used.”
The regulator made its decision based on four human trials — conducted in the United Kingdom, Brazil and South Africa; and the federal department said the two-shot regimen has an efficacy of 62.1 per cent. It added there have been no deaths or life-threatening events related to the vaccine.
“Based on the available data, the vaccine at the indicated dose was considered safe and well-tolerated,” Health Canada said in its decision.
Here’s what we know about the new dose.
How is it given?
Like the two vaccines currently on the market, the AstraZeneca/Oxford vaccine is a two-dose regimen, given between four and 12 weeks apart.
The vaccine dose is 0.5mL of a colourless to slightly brown solution that is injected intramuscularly, normally into the arm.
Who can take it?
People 18 and up.
Who should not take it?
Anyone allergic to the ingredients in the vaccine, anyone who had an allergic reaction to the first dose, or anyone with COVID-19 symptoms. For other questions, ask your doctor.
Does it work in older people?
The trials included relatively few older adults, leading the European regulator to conclude there wasn’t enough information to definitely conclude the vaccine worked in seniors, but that protection was expected.
Health Canada said there is “limited information” from clinical trials on the efficacy of the vaccine in those over the age of 65.
However, they also say that “emerging real world evidence” from countries where the vaccine is being used suggests “a potential benefit and no safety concerns.”
How is it different from the Pfizer and Moderna vaccines?
AstraZeneca’s vaccine uses a different technique than the two vaccines developed by Moderna and Pfizer, which relied on new mRNA technology.
Its approach is called a viral vector, which uses a virus normally found in chimpanzees to sneak the DNA for a coronavirus spike protein into your body, which then teaches your immune system how to fight off a future potential infection from the actual coronavirus.
Doses are expected to be cheaper and can be stored in a normal fridge, which would be a win for poorer countries.
“It’s more nimble,” as Saxinger puts it.
“It’s fairly inexpensive and easy to mass produce and store, comparatively, so you can get it to remote places much more easily, and it can possibly be given in doctors’ offices, as just usual refrigeration is needed.”
How well does it work?
According to Health Canada, getting two full doses of vaccine is between 62.1 and 59.5 per cent effective.
Isn’t 62.1 per cent a little low?
While this isn’t quite as high as Moderna and Pfizer, experts say it’s still higher than the 50 per cent efficacy rate vaccine makers were aiming for, and isn’t far off from the usual efficacy rate of the annual flu vaccine.
“(If ) you look back, for example, just to last year, the effectiveness of the flu vaccine against the most common strain was about 64 per cent; across the next common strain it was about 54 per cent,” Sharma said.
In addition, this vaccine has also proven to be effective in reducing serious illness and death.
Saxinger cautioned people not to get hung up on efficacy numbers here: “A few months ago, people would’ve been clamouring for a 70 per cent effective vaccine,” she said.
“It’s important for everyone to realize that protection from severe disease is excellent for all of the vaccines so far.”
Why did it take so long to get approved?
While both Pfizer and Moderna got the green light not long after submitting their final trial results, AstraZeneca has been in limbo for weeks.
Observers point to some confusion about the efficacy of this vaccine early on, based on a dosing error during testing that saw some volunteers get a half dose for their first shot.
Back in November, AstraZeneca said its vaccine was about 72 per cent effective overall, but ranging from as low as 62 per cent to as high as 90 per cent.
In a news release, the company revealed it had mistakenly tried out two different doses in one of its trials — and that had led to two different results.
While two full doses was about 62 per cent effective, the mistaken half dose appeared to raise that number to 90 per cent, but only in a small sample, and researchers aren’t sure why.
As a result, the regulator’s job was “a bit more complicated” this time around, Sharma told reporters in January.
Given the need to make sure the data was clear, Saxinger called the delay here “appropriate.”
In the end, Health Canada followed in the footsteps of regulators in the European Union and Britain by authorizing two full doses, because that’s the regimen tested on more people to date.
What about the variants?
This month, South Africa halted the rollout of this vaccine because of concerns it would be less effective against B. 1.351, the virus variant now dominant there.
A relatively small trial of 2,000 people suggested the vaccine offered “minimal protection” against mild and moderate cases, though research continues and experts haven’t ruled out the vaccine’s effectiveness against serious cases.
Right now, there are relatively few cases of the variant in Canada, but experts say this will have to be watched.
However, the vaccine seems to be just fine when faced with B. 117, the variant that emerged in the U.K. AstraZeneca has been a major pillar of vaccination efforts there.
The World Health Organization is still recommending the use of AstraZeneca’s vaccine, even in countries where variants emerged as dominant.
What about transmission?
All of the vaccines were designed to do one, big thing: stop someone exposed to the coronavirus from getting the illness.
But in order to achieve herd immunity, the vaccines will need to do something else: stop a person exposed to the coronavirus from giving it to others.
Determining how good these vaccines are at stopping transmission takes time, so for many doses, this was a question we just couldn’t answer yet.
However, there’s some possible good news on that front for AstraZeneca.
Research done by British researchers — which still needs to be peer-reviewed, or vetted by other scientists — suggests that vaccinated people may be less infectious.
The study didn’t look at transmission directly (for example, it didn’t test the family members of those who had been vaccinated), but it took nasal swabs from study participants and found that the rate of positive PCR results fell by half after two doses.
What are the side effects?
According to the United Kingdom, where the shot is already in use, very common side effects include tenderness, pain or bruising at the injection site, as well fatigue, headache or joint pain.
It’s also common to experience a fever or flu-like symptoms.
More uncommon symptoms include feeling dizzy, decreased appetite, abdominal pain and enlarged lymph nodes.
According to Health Canada, the most commonly reported adverse infections were tenderness (75.3 per cent) and pain (54.2 per cent) at the injection site, fatigue (62.3 per cent), headache (57.5 per cent) and myalgia, or muscle pain (48.6 per cent).
Most reactions were mild or moderate.
“I think Canada is hungry for vaccines; we’re putting more on the buffet table to be used.”
DR. SUPRIYA SHARMA SENIOR MEDICAL ADVISER WITH HEALTH CANADA
How is it transported?
According to the company, the vaccine can be stored, transported and handled at “normal refrigerated conditions,” meaning between two and eight degrees Celsius for at least six months.
It can be given in “existing health-care settings.”
This will make it easier to transport that the existing vaccines, both of which are transported frozen, or in the case of Pfizer, in ultra cold temperatures, according to Health Canada.