Dose Eligibility
Fall 2025 Vaccine Clinic Eligibility
General population, 6 months of age and older, who do not belong to the below populations may receive a vaccine in the fall, starting on October 27, 2025.
Individuals in High-Risk Group 1 should receive a vaccine in the fall AND spring:
Adults 80 years and older, 65 to 79 years of age should receive a dose now and may receive an additional dose in the spring
Adult residents of long-term care homes and other congregate living settings for seniors
Individuals 6 months of age and older who are moderately to severety immunocompromised (due to specific underlying condition or treatment)
Individuals 55 years and older who identify as First Nations, Inuit, or Metis and their non-Indigenous household members who are 55 years and older
Individuals in High-Risk Group 2 should receive a vaccine in the fall only:
Residents in long-term care homes and other congregate living settings aged 17 years and under
Pregnant individuals
Individuals from First Nations, Métis and Inuit communities who are aged 54 years and under
Members of underserved communities
Health care workers and other care providers in facilities and community settings as per NACI
The following priority populations may receive a vaccine in the fall:
Children 6 months to 4 years of age
Individuals with significant exposure to birds or mammals through interactions with birds or mammals (e.g. poultry, livestock, slaughterhouse/processing plant workers, wildlife officers/researchers, and veterinarians)
First Dose
All residents 5+
Second Dose
There is emerging evidence that longer intervals between the first and second doses of COVID-19 vaccines result in more robust and durable immune response and higher vaccine effectiveness.
The recommended interval is:
Pfizer-BioNTech - two doses at least 56 days apart.
Moderna - two doses at least 56 days apart.
AstraZeneca - two doses at least 56 days apart.
Third Dose
The Ontario government has announced that the following populations are eligible for third dose COVID-19 vaccination with the vaccine product authorized for their age group.
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Who:
Individuals 18 years of age and older.
Must be 18 years of age at the time of immunization.
Interval criteria: A minimum of 84 days after SECOND dose
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Who:
5 to 11 years of age at time of immunization.
Interval criteria:
A minimum of 6 months after SECOND dose is recommended.
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Who:
Adolescents 12 to 17 years of age at time of immunization.
Interval criteria:
A minimum of 168 days after SECOND dose is recommended and associated with a lower risk of myocarditis and pericarditis.
With informed consent, youth 12-17 years of age may receive a booster dose at a minimum of 84 days after completion of their second dose of a 2-dose primary COVID-19 vaccine series.
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Who:
Primary series completed with only viral vector vaccines.
Individuals who received two doses of AstraZeneca/COVISHIELD COVID-19 vaccine.
Individuals who received one dose of Janssen/Johnson & Johnson COVID-19 vaccine.
Interval criteria:
A minimum of 84 days after SECOND dose
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Who:
Residents of long-term care homes, retirement homes, elder care lodges, and older adults living in other congregate settings (e.g., assisted-living facilities, chronic care hospitals, naturally occurring congregate retirement settings/congregate senior’s apartment buildings, older adults living in congregate settings for people with developmental disabilities, mental health and addictions issues, etc.).
Interval criteria:
A minimum of 84 days after SECOND dose
Third Dose Frequently asked questions
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Pfizer is currently the only vaccine that will be offered to youth ages 12 to 17 at vaccine clinics across Durham Region.
For individuals 18 years of age and older, either Moderna or Pfizer vaccine may be used as a third dose (regardless of which COVID-19 vaccine was used in the primary series). Both the Moderna and Pfizer COVID-19 vaccines provide strong protection against COVID-19 and its variants. It is safe and effective to mix COVID-19 vaccines.
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It is recommended that individuals 12 years of age and older, infected with COVID-19 after their primary series but before their booster dose, receive their booster dose 3 months after symptoms started or after testing positive (if no symptoms were experienced).
For youth 12 to 17 years old, this is provided it is at least 6 months from completing the primary series.
Emerging evidence indicates that a longer interval between COVID-19 infection and vaccination is associated with improved antibody responses to COVID-19 vaccines.
COVID-19 infection is defined as a COVID-19 case confirmed by a molecular (e.g. PCR) or rapid antigen test, or an individual who is symptomatic AND is a household contact of a confirmed COVID-19 case.
With informed consent, individuals may receive a booster dose once they are considered no longer infectious, symptoms of illness are completely resolved, and their isolation period is completed.
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Pfizer is recommended for individuals aged 12 to 29 due to lower reported rates of myocarditis/pericarditis following vaccination with Pfizer compared to Moderna. Moderna can be administered with informed consent of this increased risk.
Three dose primary series
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Who: Individuals 5 years of age and older (must be at least 5 years of age at the time of vaccination) with one of the medical conditions listed below:
Individuals receiving dialysis (hemodialysis or peritoneal dialysis).
Individuals receiving active treatment (e.g., chemotherapy, targeted therapies, immunotherapy) for solid tumour or hematologic malignancies. Active treatment includes patients who have completed treatment within 3 months.
Recipients of solid-organ transplant and taking immunosuppressive therapy.
Recipients of chimeric antigen receptor (CAR)-T-cell therapy or hematopoietic stem cell transplant (within 2 years of transplantation or taking immunosuppression therapy).
Individuals with moderate to severe primary immunodeficiency (e.g., DiGeorge syndrome, Wiskott-Aldrich syndrome).
Individuals with HIV with prior AIDS defining illness or prior CD4 count ≤ 200/mm3 or prior CD4 fraction ≤ 15% or (in children 5-11 years) perinatally acquired HIV infection
First, second and third dose interval: Minimum 56 days between each dose.
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Who: Individuals 5 years of age and older (must be at least 5 years of age at time of immunization) receiving active treatment with the following categories of immunosuppressive therapies: anti-B cell therapies* (monoclonal antibodies targeting CD19, CD20 and CD22), high-dose systemic corticosteroids (refer to the CIG for suggested definition of high dose steroids), alkylating agents, antimetabolites, or tumor-necrosis factor (TNF) inhibitors and other biologic agents that are significantly immunosuppressive.
*Active treatment for patients receiving B-cell depleting therapy includes patients who have completed treatment within 12 months.
First, second and third dose interval: Minimum 56 days between each dose.
Fourth Dose
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Who: Individuals 18 years of age and older (must be 18 years of age at the time of immunization).
Interval criteria: A minimum of 140 days after THIRD dose. With informed consent, individuals may receive a fourth dose at a minimum of 84 days after their third (booster) dose.
Bivalent Booster Dose
“The bivalent COVID-19 booster is a safe and effective way for people to better protect themselves against the most recently circulating COVID-19 variants in Ontario,” said Dr. Kieran Moore, Chief Medical Officer of Health. “As vaccine protection decreases over time, I encourage all Ontarians aged five and over to receive the booster dose they are eligible for.”
Bivalent COVID-19 booster appointments will be available to and can be booked for the most vulnerable populations, including:
individuals aged 70 and over;
residents of long-term care homes, retirement homes, Elder Care Lodges and individuals living in other congregate settings that provide assisted-living and health services;
First Nation, Inuit and Métis individuals and their non-Indigenous household members aged 18 and over;
moderately to severely immunocompromised individuals aged 12 and over;
pregnant individuals aged 18 and over; and
health care workers aged 18 and over.