A COVID-19 booster is a vaccine dose given after you have completed the primary vaccine series. It helps improve protection against COVID-19 that may have decreased over time and boosts the immune response even if you had a COVID-19 infection in the past. Health Canada authorized mRNA vaccines (Pfizer-BioNTech and Moderna Spikevax) and Novavax Nuvaxovid as booster doses regardless of which vaccine was used for your primary series.
The interval between the doses depends on the vaccine you receive, your age, your health status and if you recently had a COVID-19 infection.
It is recommended that everyone ages 5 and older get a mRNA COVID-19 bivalent booster dose:
- regardless of the number of booster doses previously received
- six months after a COVID-19 vaccine dose or a COVID-19 infection. Three months (84 days) may be considered based on age, risk and health status
- people at higher risk of getting very sick should get a bivalent booster three months (84 days) after their last dose or infection
If you received a COVID-19 booster vaccine (original or bivalent) in September 2022 or later, you are up-to-date with your vaccinations at this time. The National Advisory Committee on Immunization (NACI) is currently reviewing if/when future booster doses may be required. The mRNA COVID-19 vaccines provide good protection against hospitalization and severe illness within the 3 to 6 months following vaccination.
According to NACI, it is not expected that a booster dose be routinely given every three months. With informed consent, an additional booster dose may be given at a shortened interval of at least 3 months for people at high risk of severe illness from COVID-19.
Booster dose eligibility
Once eligible, the following groups may receive a booster dose six months after a COVID-19 vaccine dose or a COVID-19 infection:
- Infants and children 6 months to 4 years of age are not eligible at this time
- Children 5 to 11 years of age may receive the bivalent Pfizer-BioNTech (10mcg) vaccine
- Youth 12 to 17 years of age may receive the bivalent Pfizer-BioNTech (30mcg) vaccine. With informed consent, the bivalent Moderna (50 mcg) may be offered to those with weakened immune systems
- Adults 18 years of age and over may receive a mRNA bivalent booster dose (Pfizer-BioNTech or Moderna)
For the following high-risk groups, a bivalent mRNA booster dose is recommended, at least three months (84 days) after last COVID-19 dose or infection:
- Residents of long-term care homes, retirement homes, Elder Care Lodges and people ages 12 and older living in other congregate settings
- People aged 65 years and over
- Immunocompromised individuals (aged 12 years and older) who are at high risk of severe illness from COVID-19, including those with underlying medical conditions
- First Nation, Inuit and Métis adults and their non-Indigenous household members (aged 18 years and older)
- Pregnant Individuals (aged 18 years and older)
- Healthcare workers (aged 18 years and older)
- Adults in racialized and/or marginalized communities affected by COVID-19
For those eligible, bivalent boosters are recommended over monovalent boosters. The bivalent mRNA booster dose is only authorized for use as a booster dose:
- Bivalent Pfizer-BioNTech is the only bivalent vaccine authorized for five to 17 year olds
- There is no preference between bivalent Pfizer-BioNTech and bivalent Moderna for people 18 years of age and older.
The original (monovalent) vaccines are to be used for all primary series vaccinations because they provide a strong initial immune response. For people who are not able or willing to receive a bivalent mRNA booster dose, the original vaccine may be offered.
With informed consent, all COVID-19 booster vaccines for people aged 5 years and older, can be given with, or at any time before or after, non-COVID-19 vaccines.
Novavax Nuvaxovid (0.5mL) is an option for people 18 years of age and older, who have not been able, due to contraindications, or are not willing to receive a mRNA COVID-19 booster vaccine.
People who received Janssen COVID-19 vaccine for their primary series are recommended to receive a mRNA COVID-19 vaccine for their booster dose.
Book an appointment for a booster dose at our City-run clinics or pharmacies. Find out where to get vaccinated.
Note: People who are moderately to severely immunocompromised may use this referral form or letter from your physician, to identify optimal timing for vaccination.