Proof of the condition is required at the clinic (i.e. referral form, letter from a specialist or primary care provider). All clients should consult their doctor before receiving their third dose. Please verify any treatment or timing considerations.

Ontario’s Chief Medical Officer of Health has announced third doses of COVID-19 vaccine are now available to specific vulnerable populations. The third dose will provide those with highest-risk health conditions an improved immune response against COVID-19.

You may register for a third dose of COVID-19 vaccine if you have one of the following highest-risk health conditions:

  • Individuals receiving active treatment (e.g., chemotherapy, targeted therapies, immunotherapy) for solid tumor 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 Stage 3 or advanced untreated HIV infection and those with acquired immunodeficiency syndrome.
  • Individuals 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.

For medically eligible, third doses may be scheduled a minimum of eight weeks (56 days) after the date of an individual’s second dose. To verify the date of your second dose you can visit and sign in using your green photo health card.

***Note: If the above conditions are not met you may be turned away at the clinic.

  • Residents of high-risk congregate settings including long-term care homes, higher-risk licensed retirement homes and First Nations elder care lodges are also eligible for a third dose.
    • Residents of these facilities will receive vaccinations onsite and do not need to book an appointment.
    • For Long Term Care, High Risk Retirement and First Nations elder care residents, the third dose should be scheduled a minimum of 5 months after the second dose.
    • For a retirement home to be deemed “high-risk” it must be directly attached to a long-term care home facility. The only high-risk retirement homes in the County of Lambton are Vision, Fiddicks, and Twin Lakes Terrace.

Have Questions? Please contact our Vaccine Call Centre at 226-254-8222 Monday to Friday from 9:00 a.m. to 4:00 p.m.

Third Dose: Register