Health Canada approves two more COVID-19 vaccines for people over 18
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Health Canada approved the Oxford University-AstraZeneca COVID-19 vaccine and a comparable one made in India, clearing the way on Friday for shots from four different companies to be used in Canada.
Canada has purchased 20 million doses directly from AstraZeneca but the contract only allowed for deliveries after March.
On Friday, Prime Minister Justin Trudeau announced that the government will also buy two million of the shots made by the Serum Institute of India. It is also making the AstraZeneca vaccine, but through a different manufacturing process. The shot from India is called CoviShield; the vaccine is sponsored in Canada by Verity Pharmaceuticals.
Canada will receive 500,000 shots from the institute in March and the remaining 1.5 million doses will arrive by May.
It’s expected that the approval of the shots will speed up Canada’s timeline for inoculations. The federal regulator approved the latest protection against COVID-19 for individuals over 18 years of age. Canada has also authorized the use of the Pfizer-BioNTech and Moderna vaccines, all are administered in two shots.
In its regulatory decision on the AstraZeneca shot, Health Canada said the vaccine has an estimated efficacy of 62 per cent.
“Overall, there are no important safety concerns and the vaccine was well tolerated by participants,” the regulator said in its decision.
The vaccine’s efficacy is well below the 94-per-cent efficacy of the Moderna shot and the 95-per-cent efficacy found with the Pfizer shots. On Friday, Health Canada’s senior medical adviser, Supriya Sharma, said “the key numbers that are important” are that the vaccines prevent serious illness, hospitalizations and death. No one who received the shots died from COVID-19 and no one who contracted COVID-19 after receiving the shot was hospitalized.
Health Canada said the two shots from AstraZeneca and the Serum Institute of India should be administered between four and 12 weeks after the first shot.
Dr. Sharma said the data suggest the shot will have more efficacy with the longer interval between shots.
Some European countries have raised doubts about the vaccine’s efficacy for the elderly, but the European regulator in January approved it for all age groups and Health Canada did as well. In its written authorization, the federal regulator said clinical trial data were “too limited” to give a reliable estimate of the vaccine’s efficacy for people over 65 years of age.
But it said its efficacy in seniors is supported by other data, from emerging real world evidence where the vaccine has already been deployed.
The data “suggest at this point in time a potential benefit and no safety concerns. Efficacy in this age group will be updated as additional data become available from currently ongoing trials,” Health Canada said.
The arrival of a new vaccine with a different efficacy profile raises new questions related to how vaccines should be allocated. Those questions include whether vaccines that have higher efficacy should be prioritized for those who are more vulnerable to COVID-19, and whether it is okay to mix doses of different vaccines, if it means people will get their shots more quickly.
The National Advisory Committee on Immunization is considering those issues and its recommendations related to the AstraZeneca vaccine will be published next week.
In its decision on the shot from the Serum Institute, the regulator said it is comparable with AstraZeneca’s shot. Health Canada had previously said a decision on the shot from the Serum Institute would be made only after its decision on the vaccine from AstraZeneca.
The federal government will also receive 1.9 million AstraZeneca shots through an internationally managed fund that was primarily set up for low- and middle-income countries. Those doses will arrive by the end of June.
Where the AstraZeneca vaccine will offer an advantage is its ease of transport and delivery.
Unlike the mRNA vaccines from Pfizer and Moderna, AstraZeneca’s consists of an adenovirus – a virus that is not harmful to people – which has been engineered to carry a portion of coronavirus DNA. Once that DNA makes its way into human cells, it induces the cells to produce the coronavirus spike protein, which alerts immune cells to defend against anything that looks similar.
Because DNA is a more stable molecule than mRNA, the AstraZeneca vaccine does not require deep freezing. It can be shipped and stored at normal refrigerator temperatures, from 2° to 8° Celsius, which makes the vaccine easier to administer.
Two additional vaccines are currently under review by Health Canada regulators. The one-dose vaccine produced by Johnson & Johnson is also based on an adenovirus. A vaccine developed by Novavax uses a manufactured protein nanoparticle and contains neither DNA nor mRNA.
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