The COVID-19 vaccines are most effective when you’ve received two doses of the same vaccine.

The first dose of your vaccine will begin to build up a protective response against COVID-19 in your body. The second dose will boost your immune response to give you long-term protection against COVID-19. Without the second dose, your body will not be able to fight the virus as effectively.

For a few people, those who are severely immunocompromised, a third dose of the COVID-19 vaccine is recommended. This is because for those people, their immune system need extra help to protect them from the virus. If you are severely immunocompromised, you should get your third dose from 2 to 6 months after getting your second dose.

For everyone else, a booster dose of the Comirnaty (Pfizer) COVID-19 vaccine is recommended if you had your second dose at least 6 months ago. This is to give you the most protection possible against COVID-19, for the longest period of time.

If you get a third dose, it is not recommended that you get a booster dose as well.

If you’re not sure if you should get a third dose, or when you should get a booster dose, have a yarn with your healthcare worker.