The Canadian province of Ontario will begin allowing residents to mix and match vaccines following updated guidance from the National Advisory Committee on Immunizations (NACI).
On Tuesday, NACI recommended relaxing rules governing the interchangeability of second coronavirus vaccine doses, saying that Canadians, who received the Oxford-AstraZeneca or its Indian analog COVISHIELD, can receive a messenger RNA (mRNA) vaccine for their second shot, namely the Pfizer-BioNTech and Moderna shots.
“Effective June 4, 2021, and in alignment with NACI’s recommendation, Ontarians who have received their first dose of the AstraZeneca COVID-19 vaccine can choose to either receive a second dose of the AstraZeneca vaccine, or an mRNA (Pfizer or Moderna) vaccine for their second dose,” the province said in a statement on Thursday.
Those who wish to receive the second dose of the AstraZeneca vaccine should contact the pharmacy or primary care provider where they received their first dose, the statement read.
NACI’s decision to offer an mRNA vaccine for the second dose was made after experts studied the risk of Canadians’ developing Vaccine-Induced Immune Thrombotic Thrombocytopenia following vaccination with the UK drugmaker’s vaccine and the risk of complications pertinent to vaccine mixing.
Additionally, Ontario said it stands by the advisory panel’s recommendation that first and second mRNA vaccine doses should come from the same manufacturer, however, in the event of supply shortages the Pfizer and Moderna vaccines can be considered interchangeable.
Canada’s vaccination regime has faced repeated setbacks, with the country experiencing a shortage of doses, despite the Trudeau government lauding deals with numerous vaccine manufacturers.
The vaccination program has also been undermined by inconsistent messaging and Canadian health officials’ decision to delay the time between vaccinations for up to four months.