Second Doses, What You Need to Know

Guidelines around second doses have changed a few times. Although it can be hard to follow, we see these changes as a good sign. It means that Ontario has a steady supply of vaccines and that more people will have access to second doses sooner. That means better protection against COVID-19 sooner.

mRNA Vaccines Can be Mixed

People who received either Moderna or Pfizer, mRNA vaccines, for their first dose may now receive either Moderna or Pfizer for their second dose. Both vaccines use similar mRNA technology and are safe to be used together for a vaccine series.

To ensure maximum protection against COVID-19 and the Delta variant, Ontarians should get vaccinated as soon as they can and book their second dose as soon as they are eligible.

What does this mean for booking your appointment in Chatham-Kent? It means you can book the first available appointment for an mRNA vaccine to get your second dose. That means you will be fully vaccinated and benefit from the better protection of two doses sooner.
We understand you might be concerned about the safety of mixing vaccines and want to put your mind at ease. Mixing vaccines from different companies is common. In fact, different vaccines have been used to complete a vaccine series for influenza, hepatitis A, and other viruses.

First Dose AstraZeneca, Two Options for Second Dose

People who got AstraZeneca for their first dose have two options for their second dose:
1. Get AstraZeneca for your second dose. To do this, contact the pharmacy or primary care office where you received your first dose.
2. Get Moderna or Pfizer (mRNA vaccines) for your second dose.
All vaccine options for second doses are safe, provide strong protection against COVID-19, and will count towards a complete vaccine series.
Second Doses and Variants of Concern (VOC)
Variants of Concern are mutations or changes to the COVID-19 virus that can make the virus spread easier to infect more people. Vaccination is our best protection against these variants. The Delta variant is currently of most concern for Canadians. A first dose, of any COVID-19 vaccine gives some protection against the Delta variant. However, a second dose is two times as effective against the Delta variant. That’s a big difference.

When to Book Your Second Dose

In the past few weeks, Ontario’s vaccine supply has increased. This has resulted in a faster rollout of second doses. This also means that the guidance for getting second doses has changed a few times. The province wants all Ontarians to be vaccinated as soon as they can, and to receive their second dose as soon as they are eligible to get the best protection against COVID-19.

Because second dose guidelines are changing quickly, please visit our website for more information.

For the Moderna, Pfizer-BioNTech, and AstraZeneca vaccines, fully vaccinated means two doses plus 14 days, even if those two doses are different brands. The important thing to remember is that a second dose of either Moderna, Pfizer-BioNTech, or AstraZeneca is better than no second dose at all.

If you have further questions, please  call 519.355.1071 x 1900.


Additional information is also available in the Province of Ontario news releases here:

Ontario Pauses Administration of AstraZeneca Vaccine (May 11, 2021)

Ontario Proceeding with Second Dose Administration of AstraZeneca (May 21, 2021)

Ontario Updating AstraZeneca Second Dose Guidance (June 3, 2021)

Ontario Expanding Accelerated Second Dose Booking to More Ontarians Ahead of Schedule (June 4, 2021)

Ontario Further Accelerates Second Doses in Delta Hot Spots (June 10, 2021)

Ontario Accelerates Second Doses of AstraZeneca COVID-19 Vaccines (June 12, 2021)

Statement from the Council of Chief Medical Officers of Health: Interchangeability of Authorized COVID-19 Vaccines