COVID-19 vaccine update: Guidance on the use of Pfizer BioNTech Comirnaty in immunocompromised children

Advisory Alert

Flow Diagram for COVID-19 Fall Booster Vaccination (PDF, 453 KB)

November 10, 2022

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To: Local Health System Partners


Updated guidance on the use of Pfizer-BioNTech Comirnaty COVID‑19 vaccine in immunocompromised infants and children aged 6 months to 4 years old

Please be advised that the Ministry of Health COVID-19 Vaccine Guidance has been recently updated to include new recommendations from the National Advisory Committee on Immunization (NACI) on the use of monovalent Pfizer-BioNTech Comirnaty COVID-19 vaccine in immunocompromised infants and children aged 6 months to 4 years.

Primary series recommendations for moderately to severely immunocompromised children aged 6 months to 4 years old

Please refer to the complete NACI statement (Government of Canada) for further information on the specific use of Pfizer-BioNTech Comirnaty for immunocompromised children. A list of immunocompromising conditions for which a four-dose primary schedule is required can be found in the current COVID-19 Vaccine Guidance (PDF) document.

Recommendations for COVID-19 vaccine booster doses

Guidance on the timing of COVID-19 vaccine booster doses has also been updated for high-risk populations. Persons with risk factors for severe infection are recommended to receive a booster dose 3 months (84 days) after their last dose of COVID-19 vaccine or positive test result. This is regardless of the number of previous booster doses received. Please refer to the updated COVID-19 Vaccine Guidance (PDF) for a list of high-risk populations and a flow diagram outlining timing considerations for COVID-19 vaccine booster doses. The flow diagram can be found on page 25 of the guidance document and is included within this Advisory Alert for your convenience.

Supporting your patients to receive their COVID-19 vaccine

Primary care providers have a critical role to play in protecting our communities from COVID-19. To sustain high levels of vaccine coverage, COVID-19 vaccine needs to be available, accessible, and acceptable within our communities. Public Health Sudbury & Districts needs your help to make COVID-19 vaccine a part of the routine vaccinations that you offer in your clinical practice. Please visit our COVID-19 Vaccine Clinic Communications in a Box webpage for health care providers for information on how to offer COVID-19 vaccine to your patient population, including homebound patients. If you have questions, or need support to implement the COVID-19 vaccine program in your office setting, please contact Cynthia Peacock-Rocca, COVID-19, Operations Manager at or by calling 705.522.9200 ext. 279 (toll-free: 1.866.522.9200).

Thank you for your continued support in protecting and promoting health in our communities.


Original Signed By

Dr. Penny Sutcliffe
Medical Officer of Health and Chief Executive Officer

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This item was last modified on November 14, 2022