Pharmaceutical giant AstraZeneca and its partner Oxford University said on Monday its vaccine is highly effective in protecting against coronavirus, becoming the third drugmaker to release positive data in the scientific race to curb the pandemic.
The company said it will have 200 million doses of its candidate by the end of 2020, with 700 million doses ready globally by the end of the first quarter of 2021.
The announcement comes on the heels of Pfizer and Moderna’s promising coronavirus vaccine data from their late-stage trials.
Pfizer announced on Nov. 18 that it intends to file for emergency authorization with the U.S. Food and Drug Administration days after saying its final trial results showed a 95 per cent effectiveness rate.
And last week, Moderna announced preliminary results for its vaccine, which also indicated 95 per cent effective rate.
Where does Canada stand with AstraZeneca?
In September, the federal government announced Canada has procured 20 million doses of the AstraZeneca vaccine.
But Health Canada needs to first approve the vaccine before it can be distributed.
The department said it is currently doing a rolling review of AstraZeneca’s vaccine data, meaning the company submits its trial information piece-by-piece rather than in one large chunk. It’s a way to fast track the approval process and not compromise safety and efficacy requirements.
Health Canada said it “will not make a decision on whether to authorize this or any other vaccine until it has received the necessary evidence to support its safety, efficacy and quality. Following the authorization of any vaccine submission, Health Canada will publish the evidence it reviewed in making its decision for transparency.”
It’s not known how much data Health Canada has reviewed so far, but on Monday AstraZeneca said data from late-stage studies will be published by the end of 2020.
How the vaccine works
The vaccine called, AZD1222, used a recombinant viral vector approach.
This means it used a weakened version of a chimpanzee common cold virus combined with genetic material for the characteristic spike protein of the virus that causes COVID-19. After vaccination, the spike protein primes the immune system to attack the virus if it later infects the body.
“The viral vector approach is a Trojan horse,” Raywat Deonandan, an epidemiologist and associate professor at the University of Ottawa, said. “Your body doesn’t recognize the chimp’s virus … and so it gets easy entrance into your cell. It then deploys a spike protein and then it creates a ‘target practice’ for your body allowing you to start building antibodies against it.”
Deonandan said this approach is more “conventional” compared to Moderna and Pfizer’s vaccine, which uses a completely new technology called mRNA.
Unlike AstraZeneca’s “viral vector” approach, the use of mRNA triggers the immune system to produce protective antibodies without using actual bits of the virus.
2 different dosing regimens
More than 20,000 volunteers took part in the trials, conducted in the United Kingdom and Brazil, with more data to be collected from around the world in the coming weeks.
The vaccine was assessed over two different dosing regimens.
AstraZeneca said it was most effective when it was administered as a half dose followed by a full dose at least one month apart, rather than as two full doses at least one month apart.
The company said the vaccine showed a 90 per cent efficacy in one dosing regimen, and 62 per cent efficacy in a second regimen. That averages to a 70 per cent efficacy, AstraZeneca said.
AstraZeneca’s chief executive officer Pascal Soriot said on Monday that the lower first dose of its experimental COVID-19 vaccine meant more people can be vaccinated more quickly, as the British drugmaker unveiled interim late-stage trial results.
“Being able to vaccinate more people faster is a really a big plus,” he said at a press conference.
Are there side effects?
The trial showed there were 30 cases of coronavirus in people who had two doses of the vaccine and 101 cases in people who received a placebo injection.
No hospitalizations or severe cases of the disease were reported in participants receiving the vaccine.
The company has not released details on mild side-effects, such as a sore arm or fatigue.
It is also not known how long the vaccine provides protection.
In September, AstraZeneca briefly paused its clinical trials in the U.S. after one woman developed “severe neurological symptoms” after taking the experimental COVID-19 vaccine.
The U.S. Food and Drug Administration then reviewed all safety data from the trials globally and deemed it safe to continue testing the vaccine.
The vaccine can be stored, transported and handled at normal refrigerated conditions (two to eight degrees Celcius) for at least six months, AstraZeneca said.
By comparison, Pfizer plans to distribute its vaccine using specially designed “thermal shippers” that use dry ice to maintain temperatures of -70 C.
“It does not require cold storage so the logistics make it easier to distribute. And AstraZeneca also had a pretty good manufacturing and distribution global network. So that will probably find the greatest global penetration,” Deonandan said.
“This is a global pandemic and it’s not over until it’s over everywhere,” he said.
He emphasized the importance of vaccinating across the world, as the coronavirus will keep circulating and harming people without it.
“Canadians may all be vaccinated, but if the rest of the world isn’t then we can’t travel, we can’t do international trade. Basically, allowing the coronavirus vaccine to be distributed in these countries allows us to have a civilization rather than just a pristine island. It reduced the chance of reinfection.”
He added that the more vaccines are out there, it also helps the chance of eradicating coronavirus.
Costs less than Moderna, Pfizer
The AstraZeneca vaccine is cheaper than Moderna and Pfizer
AstraZeneca previously pledged it won’t make a profit on the vaccine during the pandemic.
The vaccine, which requires two doses, is priced at approximately $3 to $4, according to the Financial Times, citing supply deals agreed through to Oct. 7.
Pfizer’s vaccine costs about $20 a dose, while Moderna’s is $15 to $25, based on agreements the companies have struck to supply their vaccines to the U.S. government.
Why it matters to Canadians
Colin Furness, an infection control epidemiologist and assistant professor at the University of Toronto, said the early data coming from AstraZeneca is “fantastic news” for Canadians, as the more choice of inoculations, the better possibility we have to save lives and stamp out the coronavirus.
“You want your eggs in many baskets,” Furness explained. “The more vaccine opportunities you have the better. The distribution barries in Canada aren’t with infrastructure, it’s with availability.”
He said it’s very important that Canadians have a “diverse” portfolio of coronavirus vaccines as sub-populations, like the elderly or people with diabetes, may respond to the injections differently.
However, he warned there is a possibility that having multiple vaccines could cause more complexities.
“If you have multiple vaccines making their way across the country at the same time, this can create chaos as you need to educate the public on how they differ. Your need to communicate and monitor who gets what vaccine. And if you don’t have a family doctor who keeps this data, it can get very complicated.”
— With files from the Associated Press and Reuters
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