COVID-19: Vaccine Eligibility & Doses

Vaccinated in the Past

Everyone six months and older is recommended to stay up-to-date with their COVID-19 vaccines, which includes completing the primary vaccine series and booster doses. 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(protein subunit vaccine) as booster doses regardless of which vaccine was used for your primary series.

The National Advisory Committee on Immunization (NACI) and the Ontario Ministry of Health recommends all eligible people get a dose of the updated COVID-19 vaccine as soon as it is available to you this fall/winter 2023. It is especially important for people who are at higher risk of COVID-19 infection or hospitalization to get the updated COVID-19 vaccine.

People at high-risk for flu and/or COVID-19 complications or hospitalization are:

• Residents and staff of congregate living settings (e.g., chronic care facilities, retirement homes)
• Pregnant people
• Seniors 65 years of age and older
• All children six months to four years of age
• First Nation, Inuit or Métis (FNIM) community, and/or who self-identify as FNIM, and their household members
• People six months of age and older with underlying health conditions
• Members of racialized and other equity deserving communities
• Health care workers and first responders

According to NACI, the updated COVID-19 vaccine may be used to complete your vaccine series or as a booster. COVID-19 vaccines are interchangeable which means that they are very similar and either vaccine can be used. You can get the updated COVID-19 vaccine, once eligible:

• Five years of age and older and it has been six months since your last COVID-19 vaccine dose or known infection (whichever one is later)
• Children six months to four years of age:
  • who completed their COVID-19 vaccination (primary) series and it has been six months since their last COVID-19 dose or infection;
  • who have not completed their COVID-19 vaccination (primary) series, can get their doses eight weeks apart

For certain people with weakened immune systems, talk with your health care provider about your risks and benefits of getting the updated COVID-19 vaccine at a shorter interval between three to six months.

See Vaccine Use by Age for details on recommended dosage and intervals.

The bivalent COVID-19 vaccines are still available to complete your primary series or as a booster dose. However, the updated vaccine that targets the XBB strain gives a stronger immune response to the more recent variants. Talk with your health care provider about the benefits and risks based on your unique situation.

The original Novavax COVID-19 vaccine (protein subunit vaccine) is an option for people 12 years of age and older.

An updated Novavax COVID-19 vaccine (XBB) was approved by Health Canada on December 5, 2023. It can be given to anyone 12 years of age and over. A single dose is authorized if someone has been vaccinated in the past with any COVID-19 vaccine. Two doses have been authorized if someone has never received a COVID-19 vaccine. The updated vaccine is not yet available. More details on how to receive the updated vaccine will be posted when available.

More Information:

Ministry of Health: COVID-19 Vaccine Guidance 

Not Vaccinated in the Past

Everyone aged six months and older is eligible to start a vaccination (primary) series with the updated COVID-19 mRNA vaccine. The Ontario Ministry of Health recommends the following:

• Six months to four year olds get:
  • Two doses of the updated Moderna vaccine at least eight weeks apart OR
  • Three doses of the updated Pfizer vaccine (3 mcg) at least eight weeks apart
  • To further improve protection and effectiveness of the vaccine, NACI and the Ontario Ministry of Health recommends eight weeks as the best interval between doses  in the primary series. Evidence will continue to be monitored and information will be updated as needed.
• Everyone five years of age and older get one dose of the updated COVID-19 vaccine

See Vaccine Use by Age for details on recommended dosage and intervals.

The bivalent COVID-19 vaccines are still available to start your vaccine series. However, the updated vaccine that targets the XBB strain gives a stronger immune response to the more recent variants. Talk with your health care provider about the benefits and risks based on your unique situation.

The original Novavax COVID-19 vaccine (protein subunit vaccine) is an option for people 12 years of age and older who have not been vaccinated in the past. An updated Novavax COVID-19 vaccine (XBB) was approved by Health Canada on December 5, 2023 but is not yet available. More details on how to receive the updated vaccine will be posted when available.

Learn more about the administration of the COVID-19 vaccine, information about the vaccines, vaccine use by age, and where to get vaccinated.

Vaccination if Immunocompromised

People with weakened immune systems and who are considered moderately to severely immunocompromised, the following recommendations apply for this fall 2023:

Vaccinated in the past:

• Get a dose of the updated COVID-19 vaccine if it has been six months since your previous COVID-19 dose or infection (which ever is later).
• A shorter interval (three to six months) may be considered based on age and risk. Talk to your health care provider about the best option for you.

Not vaccinated in the past:

• Everyone aged six months and older can complete their vaccination (primary) series AND get one more dose of the updated COVID-19 vaccine, eight weeks apart.

It is important to speak with your doctor or specialist about the timing for you to have the best possible immune response from the vaccine and minimize delays in your treatment. Let your health care provider giving you the vaccination know that you are immunocompromised.

Vaccine Use by Age

** Note: The updated COVID-19 vaccines are preferred (over previous products i.e. bivalent vaccines) as it is expected to provide stronger protection against the variants that are currently circulating.

Name	Type	Age group	Not vaccinated in the past	Vaccinated in the past1	Availability
Monovalent Pediatric Pfizer (XBB)**	mRNA	Six months to four years old	Dose: 3 mcg Three doses3, eight weeks apart	Completed a two or three dose COVID-19 series2 Dose: 3 mcg One dose Received one dose of Pfizer2: Dose: 3 mcg Two doses, eight weeks apart Received two doses of Pfizer2: Dose: 3 mcg One dose	Available late October/early November
Monovalent Pfizer (XBB)**	mRNA	Five to 11 years	Dose: 10 mcg One dose3	Dose: 10 mcg One dose	Available late October/early November
Monovalent Pfizer (XBB)**	mRNA	Twelve years and older	Dose: 30 mcg One dose3	Dose: 30 mcg One dose	Available Oct 10 – for eligible high-risk group Oct 30 – for everyone six months and older
Monovalent Moderna (XBB)**	mRNA	Six months and older	Six months to four years Dose: 25 mcg Two doses3, eight weeks apart Five to 11 years Dose: 25 mcg One dose3 12 years and older Dose: 50 mcg One dose3	Six months to four years and received one dose of Moderna2: Dose: 25 mcg One dose  Five to 11 years Dose: 25 mcg One dose 12 years and older Dose: 50mcg One dose	Available Oct 10 – for eligible high-risk group Oct 30 – for everyone six months and older
Bivalent Pfizer BioNTech	mRNA	Five to 11 years	Full Dose: 10 mcg Two doses2,3, eight weeks apart	Full dose: 10 mcg	Available
Bivalent Pfizer BioNTech	mRNA	12 years+	Full Dose: 30 mcg Two doses2,3, eight weeks apart	Full dose: 30 mcg	Available
Bivalent Moderna Spikevax	mRNA	Six months & older	Six months to 11 years Half Dose: 25 mcg Two doses2,3, eight weeks apart 12 years and older Full Dose: 50 mcg Two doses, eight weeks apart	Five to 11 years old Half dose: 25 mcg 12 years and older Full dose: 50 mcg	Available
Novavax (Nuvaxovid)4	Protein subunit	12 years+	Full Dose: 5 mcg (0.5 mL) Two doses, eight weeks apart	18 years and older Full dose: 5 mcg	Available
Novavax (Nuvaxovid) (XBB)	Protein Subunit	12 years+	Full Dose: 5 mcg (0.5 mL) Two doses, eight weeks apart5	12 years and older Full dose: 5 mcg	Unavailable

¹Children six months to four years of age who have completed their COVID-19 vaccination (primary) series and everyone five years and older can receive an updated COVID-19 vaccine at least six months since their last dose or infection. Children six months to four years of age who have not completed or started their C19 vaccination (primary) series, can get their doses at eight weeks apart. A shorter interval may be considered based on age, risk and health status. Talk to your health care provider about the best option for you.

² Where possible, the same vaccine product (Pfizer or Moderna) used for starting a series should also be used to complete a series.

³ Moderate to severely immunocompromised people, who are unvaccinated and aged six months and over, are eligible for an additional dose

⁴Novavax XBB.1.5. Omicron subvariant COVID-19 vaccine was approved by Health Canada on December 5, 2023 but is not yet available. More details on how to receive the updated vaccine will be posted when available

⁵ The National Advisory Committee on Immunization (NACI) recommended interval between COVID-19 vaccine doses in the primary series is eight weeks

Post-Transplant Re-Vaccination

Re-vaccination is recommended with a new COVID-19 vaccine series given the loss of immunity following:

• hematopoietic stem cell transplant (HSCT)
• hematopoietic cell transplants (HCT) (autologous or allogeneic)
• CAR-T-cell therapy

Optimal timing should be determined on a case-by-case basis in consultation with your clinical team:

• Six months to four years old should get either two doses of the COVID-19 Moderna XBB vaccine or three doses of COVID-19 Pfizer XBB vaccine; eight weeks apart
• Five years and older should get one dose of the updated COVID-19 vaccine

You may bring a letter to your vaccination appointments, highlighting the optimal timing to restart your COVID-19 vaccine series.

Residents Without OHIP Cards

Learn more on where people without OHIP cards can get vaccinated.

If You Received a Vaccine Outside of Ontario/Canada

Everyone six months of age and older, who has been vaccinated with one or more non-Health Canada approved vaccine(s), are recommended to get a dose of the updated COVID-19 vaccine if it has been six months since your last COVID-19 vaccine or infection.

It is especially important for those at high-risk of severe illness or hospitalization, to get the updated COVID-19 vaccine this fall 2023.  A shorter interval (three to six months) may be considered based on age and risk. Talk to your health care provider about the best option for you.

To keep your vaccine records updated, document any dose(s) received outside of Ontario or Canada.

Previous COVID-19 Infection

Even with a previous COVID-19 infection, people who have not started a vaccine series or those who are previously vaccinated, are still strongly recommended to get the updated COVID-19 vaccine. Immunity from an infection may not last and people can be infected with COVID-19 again.

Hybrid immunity means having protection from being vaccinated for COVID-19 and a recent past COVID-19 infection. A past COVID-19 infection can provide natural immunity, but it does not last long – especially with current variants. You have a higher risk of getting COVID-19 again if you are not up-to-date with your vaccinations.

If you have had COVID-19 in the past you should still stay up to date with your vaccinations to get the benefit of hybrid immunity.

Every COVID-19 infection increases the risk for long COVID. To maximize the immune response after you have had COVID‑19, you should wait the following intervals after symptoms started or a positive test (if you had no symptoms) before receiving your next dose.

If starting or completing your vaccination series:

• Two months if you are not immunocompromised and have no history of multisystem inflammatory syndrome in children and adults (MIS-C and MIS-A)
• One to two months (28 to 56 days) if you are immunocompromised and have no history of MIS-C or MIS-A
• If you have a history of MIS-C, until clinical recovery has been achieved or up to 90 days since the onset, whichever is longer, regardless of immunocompromised status

If you have been previously vaccinated:

• Six months since your previous COVID-19 infection
• A shorter interval (three to six months) may be considered based on age and risk. Talk to your health care provider about the best option for you