COVID-19 vaccine update: Recommendations on expanded booster dose eligibility to protect against Omicron variant

Advisory Alert

December 17, 2021

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To: Local Health System Partners


Expanded eligibility for booster of COVID-19 vaccine

This Advisory Alert outlines new recommendations from the Ontario Ministry of Health regarding the expansion of booster dose eligibility for the COVID-19 vaccines in follow-up to the Advisory Alert issued December 6, 2021.

With Omicron rapidly becoming the dominant strain of COVID-19 in Ontario, it is highly recommended that all eligible individuals get a booster dose as soon as possible in alignment with the Ministry of Health COVID-19 Vaccine Third Dose Recommendations and the Government of Ontario announcement on expanded eligibility for booster doses. It remains important for everyone else to get their first or second dose if they have not already.

Support for vaccination of eligible individuals

To support Public Health’s endeavour to quickly increase vaccination capacity we ask that participating pharmacies and primary care offices support COVID-19 vaccination and answer the call to ​increase booster capacity ​and execute clinics plans over the next two weeks.

We are sensitive to the fact that the workforce is strained, and that holiday season vacations are planned. We also recognize that surging staffing to support vaccination efforts may require reduction or elimination of some activities to support staffing of vaccination clinics.

As per the Chief Medical Officer of Health memo, we are asking all health system partners to contribute to this booster effort in the coming weeks. Specific requests are as follows:

Participating pharmacies and primary care offices can also request vaccines to offer opportunities in their practices.

Process to request vaccines

Health care providers who would like to be onboarded to the vaccination program please contact us at To request additional COVID-19 vaccines please contact us at Primary care has multiple roles to play in the vaccine program including onboarding practices to administer the vaccine in their offices, supporting vaccination clinics, and ongoing patient education on vaccine safety and efficacy.

Boosters (fourth doses) for moderately to severely immunocompromised

Effective immediately, moderately to severely immunocompromised individuals who have received three doses of their primary series may receive a booster dose (fourth dose) approximately 3 months (84 days) [updated] after the third dose in their extended series.

Expanded eligibility for booster doses to include 18 years of age and older

Starting December 20, 2021, individuals 18 years of age and older will be eligible to receive a booster dose at least 3 months (84 days) after their second dose.

Ongoing eligibility for a booster dose of the COVID-19 vaccine

The Government of Ontario is accelerating the booster dose interval to 3 months (84 days) after receiving their second dose, for the following individuals:

For a complete list of these eligible individuals, please visit:

For more information on the rationale and options for vaccine type and dose offered for COVID-19 vaccine booster doses in certain populations see Table 2 of the Government of Ontario’s Third Dose Recommendation (PDF).

Pfizer-BioNTech Comirnaty preferred for those ages 18 to 29.

Per Ministry of Health COVID-19 Vaccine Administration Guidance, individuals aged 18 to 29 are now preferentially recommended to receive the Pfizer-BioNTech Comirnaty vaccine. Based on second dose data the Pfizer-BioNTech Comirnaty vaccine has lower reported rates of myocarditis and pericarditis compared to Moderna Spikevax. This is in alignment with direction from the National Advisory Committee on Immunization.

Local Vaccination Opportunities

Please visit our Vaccination clinics for COVID-19 webpage for information on clinic dates, times, and locations. Clients can also book an appointment online at or by calling 705.674.2299 (toll-free: 1.800.708.2505), between 8 a.m. and 6 p.m., Monday to Friday. A small number of clinics will continue to offer walk-in opportunities; however, those clinics will be clearly labeled on our vaccine clinic webpage, so unless walk-in opportunities are specified, clinics will be by appointment only. Clients can also contact a local participating pharmacy.

Additional information

For more information on the COVID-19 vaccines, as well as for specific answers to your frequently asked questions visit our FAQ web page or call Public Health Sudbury & Districts at 705.522.9200 (toll-free 1.866.522.9200).


Original Signed By

Stacey Gilbeau, Registered Nurse, BScN

Program Director, School Health, Vaccine Preventable Diseases and COVID Prevention


Please note that email addresses of some recipients were provided to Public Health Sudbury & Districts by the College of Physicians and Surgeons of Ontario (CPSO) for the purpose of communications related to COVID-19. If you prefer to no longer receive Advisory Alerts from Public Health, please reply to this email requesting to be removed from our distribution list.

NOTE: All Advisory Alerts are found on our website.

This item was last modified on December 17, 2021