Hamilton’s COVID-19 vaccination program update: Changes to second dose intervals for COVID-19 vaccine

HAMILTON, ON - In alignment with provincial direction, effective March 10, 2021, second doses for the COVID-19 vaccine were extended to a 16-week interval. This direction follows the recommendation from the National Advisory Committee on Immunization (NACI) to extend the interval for second doses when vaccine is in limited supply in order to increase the number of people who are protected from COVID-19.  This is especially important as the new variant is circulating, and cases continue to rise locally. The 16-week interval for the second dose applies to the three two-dose vaccines currently approved by Health Canada (Pfizer-BioNTech, Moderna and AstraZeneca).

Anyone who has an appointment booked for a second dose on or after March 10th is being contacted by text, email or phone to reschedule.  It is vital that people arrive for their 16-week interval second dose appointment as scheduled. Those who arrive at a vaccination clinic without an appointment, or at the time of their previously scheduled second dose, will be turned away. All vaccination clinics are by-appointment only, walk-ins are not permitted.

The following groups will continue to receive vaccine at the initial intervals as described in the product monographs:

• residents of long-term care homes, retirement homes, Elder Care Lodges and Assisted Living facilities who are at the greatest risk of both exposure to COVID-19 and serious illness and death; and,
• remote and isolated First Nation communities (currently supported by Operation Remote Immunity) given the potential seriousness of COVID 19 infection in these communities with limited available health care facilities and resources. Further discussion on dosage intervals for administering to the Indigenous population beyond Operation Remote Immunity will occur.

The rationale for this provincial decision includes:

• Current evidence from real-world experience with the Pfizer-BioNTech and Moderna vaccines indicates high vaccine effectiveness against symptomatic disease, hospitalization and death from COVID-19 for two months after the first dose, including among older populations. Clinical trials with the AstraZeneca/COVISHIELD vaccine indicate that vaccine efficacy increases with the length of the interval between doses over 12 weeks.
• Based on principles of immunology, vaccine science and modelling, this short-term protection is not expected to quickly drop off.
• In jurisdictions where this extension has been in place for some time (United Kingdom, Israel, etc.), evidence shows it has helped to control the pandemic much more successfully. 

We need to work together to reduce the spread of COVID-19 in our community, to reserve healthcare and hospital capacity and to protect vulnerable settings.

Quick Facts

• Vaccination phasing and sequencing will continue to be released for additional categories as per the direction of the provincial government.
• All vaccination planning is based on and contingent on available COVID-19 vaccine supply.
• It is vital that members of the public, even those who have been vaccinated, ensure that public health measures still be practiced until it is safe and said to be safe by the health professionals in all levels of government.  Public health measures include:  
  • stay home if you are feeling unwell
  • get tested for COVID-19 if you have symptoms or have been in close contact with a confirmed positive case of COVID-19
  • limit gatherings to only members of your immediate household
  • maintain a physical distance of at least 6 feet or 2 meters from others outside of your immediate household
  • wear a mask or face covering indoors and outdoors when not able to maintain physical distancing
  • wash hands frequently

Additional Resources

• Read more about Ontario’s COVID vaccination program.
• www.hamilton.ca/COVIDvaccines
• www.hamilton.ca/coronavirus
• https://covid-19.ontario.ca
• Public Health Services’ COVID-19 Hotline: 905-974-9848 or [email protected]