Updated guidance on AstraZeneca second dose options

Advisory Alert

June 3, 2021

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To: Health Care Providers


Using a different COVID-19 vaccine for dose two can be done safely

This Advisory Alert is being issued to provide additional guidance in follow-up to our Advisory Alert dated May 25, 2021. The Ministry of Health has provided additional direction for second dose administration for individuals who received the AstraZeneca COVID-19 as their first dose.

Two options for clients who received AstraZeneca for dose one

Effective June 4, 2021, and in alignment with NACI’s recommendation (PDF), Ontarians who received their first dose of the AstraZeneca COVID-19 vaccine can choose to either receive a second dose of the AstraZeneca vaccine or an mRNA (Pfizer or Moderna) vaccine for their second dose.

Either second-dose option is available to individuals who received their first dose of the AstraZeneca vaccine and will count as a completed series. Both options are safe and will provide strong protection against COVID-19. These second dose options will be provided at the recommended 12-week interval.

AstraZeneca for dose one with AstraZeneca for dose two

Beginning June 4, 2021, individuals who received their first dose of the AstraZeneca COVID-19 vaccine 12 weeks ago and who would like their second dose of the AstraZeneca vaccine, can contact the pharmacy or primary care provider where they received their first dose to book an appointment for their second dose. A shipment of AstraZeneca is expected for the week of June 14 for second dose allocations.

AstraZeneca for dose one with mRNA vaccine for dose two

Individuals who received their first dose of the AstraZeneca COVID-19 vaccine and are opting to receive an mRNA vaccine for their second dose can contact a participating pharmacy where the Pfizer or Moderna vaccines are administered to schedule their second dose. Alternatively, they may attend a clinic offered by Public Health Sudbury & Districts by calling the booking centre at 705.674.2299 (toll-free: 1.800.708.2505), between 8 a.m. and 8 p.m., seven days a week. Beginning the week of June 7, individuals can also register for a “second dose only” at a 12-week interval through the provincial booking system.

If your office provides Moderna to your clients, you may also opt to receive Moderna for second dose allocations for clients who received AstraZeneca for their first dose.

Second dose rollout for mRNA vaccines

As Ontario continues to move through vaccine rollout and second dose administration, it is important to note that the National Advisory Council for Immunization also advises that the Pfizer and Moderna COVID-19 vaccines can be safely interchanged for first and second doses, only if the original mRNA vaccine is not readily available.

Additional information and resources

For additional information on the COVID-19 vaccines, as well as for specifics on how it is being rolled out locally, please visit Public Health’s COVID-19 vaccine webpage.

Everyone is encouraged to get vaccinated as soon as they can, and to complete the series with their second dose when eligibly to ensure maximum protection against COVID-19.


Original Signed By

Dr. Penny Sutcliffe
Medical Officer of Health and Chief Executive Officer

NOTE: All Advisory Alerts are found on our website.

This item was last modified on June 3, 2021