So far, Health Canada has approved four vaccines, Pfizer, Modena, AstraZeneca and Johnson & Johnson. Many people are concerned about the media reports comparing the advantages and disadvantages of the four vaccines, CTV summarizes how long does it take for these four vaccines to produce effects after vaccination and what is the efficiency rate? The differences between the 4 vaccines can be seen in this article.
Pfizer vaccine (Pfizer-BioNTech)
Pfizer was the first vaccine approved by Health Canada. According to government information, the Pfizer vaccine was 52.4% effective after the first dose and 92% effective 14 to 21 days after the first dose.
One week after the second dose, the Pfizer vaccine will be 95 per cent effective.
Moderna vaccine (Moderna)
The Moderna vaccine was approved by Health Canada in late December 2020, with data showing 80% efficacy after the first dose and 92% efficacy after 14 days of the first dose.
It is up to 94% effective two weeks after the second dose of vaccine.
AstraZeneca vaccine (AstraZeneca)
AstraZeneca vaccine is 76% effective after 22 to 90 days of the first dose.
The second dose of AstraZeneca vaccine is nearly 63% effective after two weeks. If the second dose is administered 12 weeks or more after the first dose, the vaccine is 82% effective in preventing the virus, and the longer it is administered, the more immune the vaccine recipient becomes.
Johnson & Johnson Vaccine (Johnson & Johnson)
Johnson & Johnson was the first single-dose vaccine approved in Canada and was 66% effective at two weeks after vaccination, and immunity in vaccinees gradually increased over time.