NACI (the National Advisory Committee for Immunization) recommends:
Starting in the spring of 2023, an additional booster dose may be offered 6 or more months from the last COVID-19 vaccine dose or infection to the following individuals who are at increased risk of severe illness from COVID-19:
• Adults 80 years of age and older
• Adults 65 to 79 years of age, particularly if they do not have a known history of SARS-CoV-2 infection
• Adult residents of long-term care homes and other congregate living settings for seniors or those with complex medical care needs
• Adults 18 years of age and older who are moderately to severely immunocompromised due to an underlying condition or treatment
You can check your eligibility and arrange a time for your vaccine via the Durham Public Health site: https://www.durhamvaccinebooking.ca/