OTTAWA (AP) – Canada’s National Advisory Committee on Immunization is now recommending that people who received the first dose of AstraZeneca’s COVID-19 vaccine receive either Pfizer-BioNTech or Moderna for the second.
Previously, the committee had indicated that those vaccinated with AstraZeneca could opt for the same vaccine or for an mRNA vaccine for the second dose. But in the new recommendations released Thursday, it indicates that it is now “preferable” to use Pfizer or Moderna for the second dose.
The guidance is based on the evidence that a second dose with an mRNA vaccine produces a stronger immune response, and the low, but severe, risk of developing thrombi associated with the AstraZeneca vaccine.
The recommendation does not mean that people cannot opt for AstraZeneca if they choose to, or if they are allergic to mRNA vaccines.
“People who receive two doses of the AstraZeneca / COVISHIELD vaccine can be assured that the vaccine offers good protection against infection and very good protection against severe illness and hospitalization,” the advisory committee said.
As of June 5, 2.1 million Canadians had received one dose of the AstraZeneca vaccine and 15,186 had received both.
There are no further AstraZeneca shipments scheduled, but approximately half a million doses are still in stock in the provinces.
During this week and next, 14 million doses of Pfizer-BioNTech and Moderna vaccines will be delivered, including a US donation of one million doses of Moderna’s COVID-19 vaccine that arrived Thursday. to Canada.
The donated doses are part of a US pledge to donate 80 million doses of the vaccines by the end of June.
Jeff Zients, the White House COVID-19 response coordinator, said the shipment to Canada was after another event to Mexico on Tuesday.