Third Dose Boosters


by the Leeds, Grenville & Lanark Health Unit

Based on guidance from the National Advisory Committee on Immunizations, Ontario is now recommending third doses of COVID-19 vaccine to optimize protection from infection for those who are most vulnerable. Third doses can be either mRNA vaccine (Pfizer or Moderna) and our clinics have a good supply of both. These third doses are recommended – not required, and those with 2 doses are still considered fully vaccinated. Most people will have good protection still with 2 doses, but those who are older, who have compromised immune systems, or those at very high risk of exposure will benefit from an additional dose for continued protection against severe disease/hospitalization.

If you are eligible for a third dose of COVID-19 Vaccine in Ontario, as per the list below, you can book an appointment at one of our clinics to receive it, or check with a participating pharmacy. 

Ontario is now recommending third doses for the following groups at an interval of 6 months (168 days) from their second dose:

– As of December 13, adults age 50–69 (born in 1952–1971). NOTE: We are encouraging those in their 50’s and 60’s to seek their booster at a pharmacy, if they are eligible in December, in order to leave room in our clinics for children’s first doses and 70+ boosters.

  • Adults 70+ years of age (born in 1951 or before);
  • Residents of Long-Term Care Homes (LTCH), Retirement Homes (RH), Elder Care Lodges, and elderly living in other congregate settings.
  • Indigenous adults (18+) and their non-Indigenous adult (18+) household members
  • Those who have received 2 doses of AstraZeneca (one dose of Johnson & Johnson)
  • Healthcare workers who frequently have close contact in the patient environment, plus others with close patient contact. Healthcare workers can likely access their third dose booster through their employer.
  • Designated essential caregivers for residents of Long-Term Care or Retirement Homes. Can likely access the third dose directly from the facility.
  • People with moderate to severe immunosuppression are recommended to have 3 doses of vaccine for optimal immune response. Immunosuppressed individuals can access their third dose through their health care provider a minimum of 28 days, but preferably 2 months after their second dose. If unable to access it from a health care provider, the Health Unit can provide it at a clinic. You can also check with a pharmacy to see if they can provide it.

Please ensure you are eligible based on the criteria above and timing (at least 168 days from second dose) before booking or attending a vaccine clinic. Those who are not eligible will be turned away.


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