Ontario's top doctor is urging people who received their first dose of the Pfizer COVID-19 vaccine to not hesitate to get their second dose with the Moderna vaccine.
"We would ask that you not reschedule any appointment to try and get a second dose of Pfizer at a later date, as we have a large supply of Moderna coming right now," Dr. David Williams, Ontario chief medical officer of health said at a press conference on Monday.
"We are saying that if you have an opportunity, that you may proceed to go ahead and use Moderna as your second dose, as compared to Pfizer, because we want you getting the full protection as soon as possible."
He stressed that both mRNA vaccines are safe and effective and use similar technology, making them safe to mix.
"One of the key strategies to slow transmission and to keep the Delta variant under control and avoid a fourth wave is to get vaccinated as soon as possible," Dr. Williams said.
"First dose does protect you from severe consequences and hospitalization, but that doesn’t interrupt transmission. Second dose does interrupt the transmission."
The City of Toronto announced over the weekend that due to delays in Pfizer shipments, city-run immunization clinics with only administer a Moderna mRNA doses to individuals 18 and older starting June 20. Pfizer supply will be reserved for children between the ages of 12 and 17, as Moderna has not yet been approved for that age group.
“While Team Toronto vaccination partners are facing a shipment delay, we must not delay the quick administration of doses," a statement from Dr. Eileen de Villa, Toronto's medical officer of health, reads.
"With the Delta variant growing at an exponential rate in Toronto, vaccines are one of our key strategies to slow transmission. Both Pfizer and Moderna mRNA vaccines are interchangeable, equally effective and safe for everyone over 18 years. If you have an appointment, keep it. If you don’t have an appointment for a first or second dose, make one as soon as you are eligible."
Peel Region will also be reserving Pfizer doses for children, set to last until at least Thursday, June 24.
Medical experts in Ontario continue to reassure the public that it is safe to mix mRNA vaccines and the public should take the first appointment available to them.