“An mRNA vaccine should now be offered as the second dose for individuals who received the first dose of AstraZeneca or [its Indian analogue] Covishield vaccine,” Canada’s Chief Public Health Officer, Dr. Theresa Tam said during a press briefing on Thursday.
There are two mRNA vaccines currently approved for use in Canada produced by Pfizer-BioNTech and Moderna.
NACI said the mixed-dose schedule provides better protection against the disease and reduces the risk of developing Vaccine-Induced Immune Thrombotic Thrombocytopenia.
Canadian public health officials have received 56 reports of blood clotting events following vaccination with AstraZeneca, with 38 of the cases being confirmed, and all were related to the first dose.
Canada’s “vaccine tzar” Krista Brodie said there are 600,000 AstraZeneca vaccine doses in circulation in the country and their future will now be determined by the provinces.
Canada’s vaccination regime has faced repeated setbacks, with the country experiencing a shortage of doses, while NACI has been criticized for inconsistent messaging and Canadian health officials’ decision to delay the time between vaccinations for up to four months based solely on acquisition schedules.