About COVID-19 Vaccines

The following information was developed for this website by medical professionals and public health experts using Canadian government and other scientific and medical sources. It is not intended as medical advice. Always seek the advice of a qualified healthcare provider with any questions you may have regarding the COVID-19 vaccine.

Vaccination against the COVID-19 virus will help protect you from getting sick or dying with COVID-19. Also, to stop the spread of COVID-19 in Canada, sufficient numbers of Canadians need to be vaccinated to stop community transmission of the virus.

Even if a person does not die of COVID-19, they may have long- term complications including memory loss, fatigue, unexplained breathing difficulties, and damage to the lungs and heart.

If enough people have immunity, the virus is less likely to spread. We need to vaccinate at least 75% of the population to achieve herd immunity and go back to our daily lives, reopen businesses, hug and see loved ones again.

No, all COVID-19 vaccines are free.

In mid-June, the National Advisory Committee on Immunization (NACI) updated its recommendations on the interchangeability of COVID-19 vaccines for second doses. An mRNA vaccine is now preferred as the second dose for individuals who received a first dose of the AstraZeneca, based on emerging evidence of a potentially better immune response from this mixed vaccine schedule.

If you received an mRNA vaccine (Pfizer BioNTech or Moderna) as your first dose, you will be offered an mRNA vaccine as your second dose. It is preferred that you receive the same type of vaccine as you had the first time, unless it’s not readily available or unknown, in which case it’s ok to receive the other type of mRNA vaccine. Both are equally safe and effective.

If you received AstraZeneca as your first dose, you may choose to get AstraZeneca as your second dose, but the NACI is now recommending that you take an mRNA vaccine for your second dose.

All vaccines approved for use in Canada equally and effectively reduce hospitalization and serious illness, and all are almost 100% effective in preventing death from COVID-19.

The important point is that you shouldn’t wait to get vaccinated with two doses for full protection. New virus variants are emerging that are causing more cases, hospitalizations and deaths, and mass vaccination is the only way to stop this.

According to Health Canada, and based on clinical trials involving tens of thousands of vaccine recipients:

Pfizer-BioNTech 95% effective after two doses

Source:  https://www.canada.ca/en/health-canada/services/drugs-health-products/covid19-industry/drugs-vaccines-treatments/vaccines/pfizer-biontech.html

Moderna 94% effective after two doses

Source:  https://www.canada.ca/en/health-canada/services/drugs-health-products/covid19-industry/drugs-vaccines-treatments/vaccines/moderna.html

AstraZeneca 62% effective after two doses (79% in North/South American studies)
Real world data shows that AZ is 80-90% effective in preventing hospitalizations.

Source:  https://www.canada.ca/en/health-canada/services/drugs-health-products/covid19-industry/drugs-vaccines-treatments/vaccines/astrazeneca.html

Johnson & Johnson 66% effective after one dose and real time data shows it’s >90% effective in preventing severe illness and hospitalization.

Source:  https://www.canada.ca/en/health-canada/services/drugs-health-products/covid19-industry/drugs-vaccines-treatments/vaccines/janssen.html

All four vaccines are highly effective in preventing severe COVID-19, hospitalization and death.

That varies between vaccines and variants.

Every COVID-19 vaccine will prevent severe illness/death from any of the variants currently circulating in Canada.

Even with vaccines showing lower effectiveness against certain strains, the manufacturers are creating new versions of their vaccines to work better against these new variants, so that you can probably get booster doses in the future which will be effective in the months and years to come.

For Pfizer-BioNTech, Moderna and AstraZeneca, two doses are needed because the first dose “primes” your body’s immune response: your body learns to make antibodies to fight COVID-19. The second dose “boosts” it for a stronger and longer-lasting immunity. Both doses are needed to provide full immunity.

The Johnson & Johnson‘s vaccine was tested and shown to protect people and provide immunity with a single dose.

Pfizer-BioNTech and Moderna: mRNA vaccines.

A small piece of mRNA that makes the COVID-19 spike protein enters your cells and teaches your body to make antibodies against the COVID-19 virus. Then the mRNA is destroyed within hours, leaving instructions behind. 

Astra Zeneca and J&J: viral vector vaccines.

These vaccines use a harmless virus (like the common cold virus) that has been weakened and then modified by adding a piece of the COVID-19 virus’s spike protein. The same process takes place as with mRNA vaccines above, triggering our body to make antibodies and to activate other immune cells.

None of them interact with or alter your own DNA!

None contain live COVID-19 virus.

All have similar side effects: pain at the injection site, tiredness, fever or flu like symptoms, headache, mild muscle/joint aches.

Health Canada has approved the Pfizer-BioNTech, Moderna, AstraZeneca and Janssen (Johnson & Johnson) COVID-19 vaccines for use in Canada.

No. Getting any vaccine, including the COVID-19 vaccine, will not affect the results of a COVID-19 test as it is not a live vaccine.