Health Canada has approved AstraZeneca’s COVID-19 vaccine for people who are 18 years of age and older. This means Canadians now have access to a third vaccine and that innoculations will likely be ramped up.
The vaccine has shown an effectiveness of about 62% in preventing symptomatic COVID-19 disease beginning 2 weeks after the second dose, Canada’s regulator has said.
The vaccine is given by 2 separate injections of 0.5 mL each into the muscle of the arm. For the vaccine to work best, you need to get 2 doses: a first dose and then a second dose 4 to 12 weeks later.
Immunity develops over time. It takes about 2 weeks to develop significant protection against COVID-19. For the greatest protection, you will need the second dose.
The AstraZeneca vaccine is vector-based unlike the Pfizer and Moderna products which are mRNA vaccines.
According to Health Canada, viral vector-based vaccines use a harmless virus, such as an adenovirus, as a delivery system. This “vector” virus is not the virus that causes COVID-19.
Adenoviruses are among the viruses that can cause the common cold. There are many different types of adenoviruses, and many have been used as delivery systems for other vector-based vaccines for decades. When a person is given the vaccine, the vector virus contained within the vaccine produces the SARS-CoV-2 spike protein. This protein is found on the surface of the virus that causes COVID-19. This protein will not make you sick. It does its job and goes away.
Through this process, the body is able to build a strong immune response against the spike protein without exposing you to the virus that causes COVID-19.
As AstraZeneca’s vaccine can be stored in a normal refrigerator, it is believed that it can easily be dispensed through pharmacies and doctors’ clinics.