Canada has now approved four different coronavirus vaccines after giving the green light to Johnson & Johnson’s COVID-19 shot.
Johnson & Johnson’s single-dose shot joins a growing arsenal of vaccines that include shots from Pfizer, Moderna and AstraZeneca to protect Canadians against COVID-19.
“At this time, we consider all available vaccines to be effective,” said Dr. Supriya Sharma, Health Canada’s chief medical advisor, at a press conference on Friday.
“Our advice to Canadians is to get whichever vaccine is available to you.”
Here’s a closer look at all the vaccines that Canada has approved so far:
Johnson & Johnson
Unlike Pfizer and Moderna’s vaccines, the Johnson & Johnson shot is an adenovirus-based vaccine.
It was built using a kind of virus, which causes colds in chimpanzees.
The adenovirus is altered to carry a gene for the coronavirus protein, which can then train a person’s immune system to recognize the actual coronavirus if it ever enters the body.
It only requires one dose and has been approved for use in individuals aged 18 and older and is effective in older adults, Sharma said.
“Almost 20 per cent of the participants in the clinical trials were 65 years of age and older, and no differences in the safety or efficacy were seen compared to the younger groups,” she said.
The shot is significantly easier to ship and store, as it can be kept in a refrigerator (between 2 C and 8 C) for at least three months — much longer than the Moderna vaccine — rather than a freezer.
In clinical trials, it showed an overall efficacy of 66 per cent in preventing moderate to severe COVID-19, Sharma said.
Canada has pre-ordered 10 million doses of the vaccine, with options to order up to 28 million more.
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AstraZeneca
AstraZeneca’s two-dose shot was approved for use on Feb. 26.
Like the Johnson & Johnson vaccine, this is also an adenovirus-based vaccine and can be stored at normal fridge temperature — meaning the doses are much easier both to ship and to keep.
The Oxford-AstraZeneca vaccine was found to be 62 per cent effective in a two-dose clinical trial.
The protocol for giving the booster shot set and used in the clinical trials for AstraZenenca was one month after the first dose.
The World Health Organization (WHO) has recommended that the AstraZeneca vaccine can be given with an interval of eight to 12 weeks.
Health Canada has approved the shot for all adults — anyone 18 years and older.
But Canada’s National Advisory Committee on Immunization (NACI) is not currently recommending the AstraZeneca vaccine for people 65 or older “due to limited information on the efficacy of this vaccine in this age group at this time.”
The first two phases of AstraZeneca’s trials did not include people over the age of 65.
Canada has purchased 20 million doses — enough to vaccine 10 million Canadians.
Moderna
Moderna’s mRNA vaccine was the second COVID-19 shot approved for use in Canada back on Dec. 23.
Moderna’s shot was manufactured using mRNA-based technology, a relatively new way to make vaccines.
Instead of injecting a deactivated form of the virus, the mRNA vaccine uses a component of the virus called messenger RNA that basically contains the genetic instructions for the human body to make the specific spike protein of the coronavirus.
By doing this, the immune system learns to recognize and respond to that specific protein, meaning it can more quickly mount a response if the virus enters the body.
The two doses are supposed to be given four weeks or 28 days apart, but many provinces are now extending that time to up to four months amid shortages, as recommended by NACI.
Clinical trials found Moderna’s vaccine to be 94.1 per cent effective in preventing COVID-19.
The Moderna doses can be stored in a freezer between -25 C and -15 C. Territories have been guaranteed priority access to this particular vaccine, as it’s easier to safely transport and store compared to Pfizer’s — which was approved first.
Canada’s agreement with Moderna is for 40 million doses — although the feds have the option of purchasing another 16 million in addition to that. The 40 million doses are enough to inoculate 20 million Canadians, over half of the population.
Pfizer
On Dec. 9, Pfizer’s coronavirus vaccine became the first COVID-19 shot to get approval in the country.
Canada has 40 million Pfizer doses secured in its agreement with the manufacturer.
Like Moderna’s jab, this is also an mRNA vaccine and requires two doses — which the company recommends be given three weeks or 21 days apart, as done in clinical trials.
Pfizer’s clinical trials were only conducted on those over the age of 16, which means that until further studies are completed in younger age groups, anyone under 16 years old is ineligible for the jab.
Of the four vaccines, Pfizer is the most demanding about temperature. This vaccine requires ultra-cold storage, meaning it has to be transported and stored at -70 C. This makes the vaccine tricky to ship to remote regions, where the appropriate infrastructure is far more difficult to set up.
On Feb. 25, Pfizer-BioNTech requested a change to allow its COVID-19 vaccine to be kept at between -25 C and -15 C instead of the earlier approved storage condition of between -80 C and -60 C.
While Health Canada still endorses ultra-cold storage conditions for the Pfizer-BioNTech vaccine, the department “after conducting a thorough review” said on Wednesday that the doses can now be stored and shipped “at standard freezer temperatures” for up to 14 days.
In terms of effectiveness, Pfizer takes the gold. At 95 per cent, it narrowly edges Moderna for a photo-finish.
Still, at the end of the day, Canadians should feel confident that any one of the approved vaccines will cut off COVID-19’s claws and protect them from the worst outcomes of the virus.
“All vaccines will help Canadians to fight the pandemic,” said Health Canada’s Dr. Marc Berthiaume at Friday’s press conference.
“The efficacy rates may vary depending on the design and studies, but we feel that overall these are very good vaccine choices.”
— With files from Global News’ Rachel Gilmore
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