COVID-19 Vaccine Second Dose Eligibility Expanding in June

Written by Communications, June 18, 2021

Residents Who Received AstraZeneca as a First Dose Can Choose an mRNA or AstraZeneca Vaccine For Their Second Dose

People who received two doses of AstraZeneca vaccine can rest assured that the vaccine provides good protection against infection, and very good protection against severe disease and hospitalization.

“For everyone, receiving the second vaccine dose is essential to provide better and longer-term protection against COVID-19 for individuals and for the entire community,” said Dr. Salvaterra, Medical Officer of Health. “Data from the UK suggests that a second dose is even more important in preventing infection from the now-circulating Delta variant.”

Yesterday, the province announced the updated plan for vaccine eligibility for an accelerated second dose. The plan is as follows:

  • Starting June 21 at 8:00 a.m., residents who have received a first dose of a messenger RNA (mRNA) COVID-19 vaccine before May 9 are eligible to book their second dose appointment for an appointment that is at least 28 days after their first dose appointment.
  • Starting the week of June 28 (exact date and time to be determined), all residents 18 years of age and older who have received a first dose of an mRNA COVID-19 vaccine are eligible to book their second dose appointment for an appointment that is at least 28 days after their first dose appointment. Residents who are booking a first dose appointment will be able to book a first and second dose at a 28-day interval.
  • As of now, residents who received the AstraZeneca COVID-19 vaccine as the first dose are eligible to receive a second dose as early as 8 weeks after the first dose appointment.

In an effort to deliver second dose vaccines to residents as quickly as possible, Peterborough Public Health will be offering both mRNA vaccines, Pfizer or Moderna, at mass immunization clinics. The National Advisory Committee on Immunization (NACI) continues to closely monitor the evolving evidence on COVID-19 vaccines, and updated its recommendations yesterday to emphasize the interchangeability of Pfizer and Moderna vaccines. Either one of these authorized mRNA vaccines can be used for either the first or second dose, depending on local availability.

“For many, this will mean your second dose vaccine may be a different brand from the first dose,” said Dr. Salvaterra, Medical Officer of Health. “In routine immunization, it is common for brands of vaccines to be used interchangeably to complete a vaccine series. It is safe to do and will provide the same protection as receiving a second dose of the same brand.”

People who received a first dose of AstraZeneca are eligible to receive a second dose between 8 to 12 weeks after their first dose. They can choose whether to receive a second dose of AstraZeneca or to switch to a mRNA vaccine. NACI has recommended that a second dose with a mRNA vaccine may provide a “potentially better immune response” based on research where the blood of recipients was examined to quantify the types and quantity of immune cells. However, there is no clinical evidence yet to indicate that immunity is better or longer lasting. For this reason, individuals will be offered both vaccines, AstraZeneca and Moderna, and will be asked to make an informed decision.

That means that patients with their second AstraZeneca dose appointment already booked at the Primary Care Evening Vaccination clinic between June 15 and June 30 will be contacted by email to advise them that clinics will have both vaccines on hand. There will be sufficient vaccine at the clinic to accommodate either choice. Patients will be provided access to a health care provider to assist with making the best choice for them.

Starting July 5, Peterborough’s primary care providers will be holding Moderna-only clinics for AstraZeneca patients who have already decided to switch to an mRNA vaccine for their second dose.

While it is important to receive the vaccine as soon as you are able to, Peterborough Public Health is asking residents to be patient when booking a vaccine appointment. Vaccine supply and clinic capacity is limited while the demand for the vaccine is still very high. Residents are encouraged to check local pharmacies for appointments. Residents can also keep up to date with appointments opening at Mass Immunization Clinics in Peterborough by following @ptbohealth on social media.

For more information about booking a second dose appointment, please visit or call the provincial vaccine inquiry line at 1-888-999-6488.



For further information, please contact:

Brittany Cadence

Communications Manager

705-743-1000, ext. 391