Dear Patients, 

With Ontario facing the most devastating wave of COVID-19 yet, and more contagious variant strains circulating, it is so important that you protect yourself and that includes through vaccination. We are encouraging you to get vaccinated as soon as you can. If you still have questions after reading this information, please call our office. 

Take the first vaccine offered to you – Waiting for your ‘preferred’ vaccine risks potentially getting COVID-19 and associated illness. To best protect yourself and others, We agree that the best COVID19 vaccine is the one that reaches your arm first. Only COVID-19 vaccines that Health Canada determines to be safe and effective are approved for use, and all are highly effective in preventing severe illness, hospitalization, and death from COVID-19, including AstraZeneca. This is the same advice we as family doctors give to our own family members and loved ones. 

Below you find some credible resources for some of the FAQs that we encounter from our patients.

  • Message regarding the AstraZeneca Vaccine
    • On May 21, Ontario’s Chief Medical Officer of Health announced that people who received their first dose of the AstraZeneca (AZ) vaccine between March 10 and March 19 may choose to get their second doses of the vaccine starting Monday, May 24 and up until May 31, 2021.
    • There is still a pause on the AZ vaccine as a first dose, announced on May 11.
    • Here is more information, including options right now, for those of you who received a first dose of the AZ vaccine.

What are my options for my second dose if I received one dose of AZ?

If you received your first dose of AZ between March 10 and 19, you may choose to get vaccinated during the week of May 24 through 31 with a shortened 10-week interval between doses. If you do not wish a shortened dose interval, you can wait to receive a second AZ dose at the 12-week interval. For those wishing the earlier second dose at the 10-week interval, please contact the location where you received your first dose to book an appointment for your second dose.

If proven to be safe and effective, you may choose to wait to have a second dose with one of the mRNA vaccines (Pfizer or Moderna) at a 16-week interval (see more information below on what we know about the evidence for mixing and matching vaccines).

For anyone vaccinated from March 20 onwards, or those vaccinated between March 10-19 who wish to have a 12-week interval between AZ doses, please stay tuned. Further details will be provided soon by the Ministry of Health on booking second doses.
Please review this consent form in the meantime for more information on options for a second dose. You can also call us to discuss the benefits and risks if you have additional questions.

What is the best interval between getting my AZ shots?

Clinical trials showed that AZ works best when the two doses are spread out by at least 12 weeks – estimated at over 80% protection against symptomatic disease versus an estimated 69% when given between nine and 12 weeks. Your personal circumstances, including COVID-19 prevalence in your community and your risk of being infected by the people around you, should be a consideration in your decision.

Is it safe to get the AZ vaccine as a second dose?

  • The AZ vaccine is approved by Health Canada.
  • We know that a second dose provides greater and significant protection than one dose alone against serious illness, hospitalization, and death from COVID-19.
  • The risk of a serious blood clot (VITT) associated with the second dose of the AZ vaccine is currently estimated at approximately 1 in 600,000, based on data from the United Kingdom. If/when you receive the AZ vaccine, know the signs of the associated rare blood clots because it can be best treated if addressed early. Please reach out to our office or seek emergency care if you have the warning symptoms. [For a quick summary of symptoms, see graphics here: https://drive.google.com/drive/folders/1Zvt1ui-FAQ2UrJZp5ABu3rST8tlEaWsF

Is it safe to get a different brand of vaccine as my second dose?

There is no published data so far on effectiveness of mixing and matching different vaccine brands, but a large clinical trial is underway with results anticipated in June 2021. The early data looking at side effects in the first few days show that mixing doses results in more significant side effects but not severe enough to land people in hospital.

Canada’s National Advisory Committee on Immunization is expected to make recommendations based on these findings in the upcoming weeks.

When can I get the COVID19 vaccine if I just had another vaccine or if I need to get another vaccine soon after?

Per NACI guidance, there should be a minimum 14-day waiting period to get the COVID-19 vaccine after any previous vaccine (e.g., shingrix/pneumovax) and additional vaccines should not be given for 28 days after the COVID-19 vaccine.

I take several prescription medications. Do I need to stop them before I get the vaccine?

No. We do not know of any medications you have to stop in order to get the vaccine.

I received the first dose of the AstraZeneca vaccine. What do I do about my second dose?

Ontario announced that it will follow the new National Advisory Committee on Immunization (NACI) recommendations on vaccine interchangeability. Individuals who received a first dose of the AstraZeneca vaccine may receive a second dose of either AstraZeneca, Moderna or Pfizer with a dose interval of 12 weeks. The rate of vaccine-induced thrombotic thrombocytopenia in individuals who receive a second dose of AstraZeneca is approximately one in 600,000. Individuals who received a first dose of an mRNA vaccine (Pfizer or Moderna) should receive the same vaccine for their second dose. If the same one is unavailable for the second dose, the vaccines may be used interchangeably. Read the province’s news release.


Where can I get updates?

We will update you as soon as we have information. You can also check the provincial and our local public health unit website.

Please book your vaccination appointment as soon as you are eligible.


Please remember – our office is open to you, by phone or in person to answer any vaccination questions. We are here to help keep you safe and get through this pandemic together.

Centro Healthcare Family Health Organization