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Fourth Doses of the COVID-19 Vaccine for Immunocompromised Individuals

Our government is continuing to take action to protect our most vulnerable Ontarians from COVID-19 and the Omicron variant, by offering a fourth dose (booster) of the COVID-19 vaccine to immunocompromised individuals three months (84 days) after they’ve completed their three-dose series.

Fourth doses are currently available after three months (84 days) following a third dose to residents of long-term care homes, retirement homes, elder care lodges, and other congregate settings that provide assisted living and health services.

Starting today at 8:00 a.m., immunocompromised Ontarians can schedule their fourth dose through the following channels: 

  • by calling the Provincial Vaccine Contact Centre at 1-833-943-3900
  • directly through public health units that use their own booking system
  • at participating pharmacies
  • hospital clinics (visit your local hospital or public health unit for booking details, if available in your region)
  • mobile or pop-up clinics, such as the GO-VAXX bus (visit your local public health unit website for details, if available in your region)
  • through your hospital’s vaccination program if you are a hospital-based health care worker

Eligible individuals can include those who are:

  • a transplant recipient (including solid organ transplant and hematopoietic stem cell transplants)
  • receiving stable, active treatment (chemotherapy, targeted therapies, immunotherapy) for a malignant hematologic disorder or solid tumor
  • in receipt of chimeric antigen receptor (CAR)-T-cell
  • an individual with moderate or severe primary immunodeficiency (for example, DiGeorge syndrome, Wiskott-Aldrich syndrome)
  • Stage 3 or advanced untreated HIV infection and those with acquired immunodeficiency syndrome
  • undergoing active treatment with the following categories of immunosuppressive therapies: anti-B cell therapies (monoclonal antibodies targeting CD19, CD20 and CD22), high-dose systemic corticosteroids, alkylating agents, antimetabolites, or tumor-necrosis factor (TNF) inhibitors and other biologic agents that are significantly immunosuppressive or are taking specific immunosuppressant medications 
  • receiving dialysis (hemodialysis or peritoneal dialysis)

Both Moderna and Pfizer vaccines provide strong protection against COVID-19 and the Omicron variant. It is safe to mix vaccines and the best vaccine for your booster is the first one available.