TORONTO — The Ontario government, in consultation with the Chief Medical Officer of Health and other health experts, including the Ontario Science Advisory Table, is further accelerating the second dose interval for individuals who received their first dose of an AstraZeneca COVID-19 vaccine to eight weeks, with informed consent, from 12 weeks.
With informed consent, individuals can choose between a second dose of AstraZeneca or an mRNA vaccine, at an eight to 12-week interval, recognizing that while waiting 12 weeks helps to ultimately provide more protection, some may choose to receive their second dose sooner to have the increased protection provided by a second dose earlier. All of these options provide protection against COVID-19, including the Delta variant, and have been deemed safe.
This decision is based on emerging clinical evidence about the administration of two doses of different vaccines, as supported by the National Advisory Committee on Immunization (NACI). Evidence from multiple studies indicates that mixing of COVID-19 vaccines (receiving an mRNA vaccine after an AstraZeneca vaccine) at dosing intervals between eight and 12 weeks is safe and demonstrates a beneficial immune response. There is evidence that a longer interval between two doses of the AstraZeneca vaccine (such as a 12-week interval) provides higher protection.
Beginning Monday, June 14, 2021 at 8:00 a.m., individuals who received their first dose of the AstraZeneca vaccine will be eligible to book their second dose appointment at an interval of eight weeks or more with informed consent.
Individuals who wish to receive an mRNA vaccine for their second dose can book an appointment through the provincial booking system, through public health units that use their own booking system, or a participating pharmacy. For individuals who wish to receive second dose of the AstraZeneca vaccine, individuals can contact the pharmacy or primary care provider where they received their first dose.
All Ontarians are encouraged to get vaccinated as soon as they can, and to receive their second dose as soon as they are eligible and within the recommended interval to ensure maximum protection against COVID-19.
Quick Facts
- Ontario is confirmed to receive approximately 4.7 million doses of the Pfizer COVID-19 vaccine in June, approximately 3.54 million doses of the Pfizer vaccine in July and over two million doses of the Moderna vaccine before the end of June.
- Eligible groups can use Ontario’s vaccine booking system to find out how to schedule an appointment, or can call the Provincial Vaccine Booking Line number at 1-833-943-3900. For general inquiries, individuals can call the Provincial Vaccine Information Line number at 1-888-999-6488 or TTY service is also available by calling 1-866-797-0007.
- Visit ontario.ca/pharmacycovidvaccine to find a pharmacy offering a COVID-19 vaccine and to book an appointment.
- Timing of second dose appointments may vary based on local considerations, vaccine supply and the date of an individual’s first dose appointment.
