Canada allows AstraZeneca vaccine recipients to get Pfizer or Moderna jab for second dose

Canada’s National Advisory Committee on Immunization says people who received the Oxford-AstraZeneca vaccine for the first dose can be offered either the Pfizer or Moderna jab for the second.

The advice affects more than 2 million Canadians who received the Oxford-AstraZeneca vaccine before provinces stopped using it for first doses last month.

The vaccine is potentially linked to a rare but serious blood-clotting syndrome.

In Canada, 41 confirmed or suspected cases of vaccine-induced thrombotic thrombocytopenia (VITT) have been diagnosed and five people have died.

Several European countries are giving Pfizer or Moderna as second doses to AstraZeneca recipients, including Denmark, Finland, France, Germany, Sweden, Norway and Spain.

NACI’s published report says AstraZeneca recipients can be offered the same vaccine if they want it or can be given either Pfizer or Moderna doses.

They say they are basing their advice on the risk of VITT, and emerging evidence that mixing and matching different types of vaccines is not only safe but may produce a better immune response.

However, Canada’s Chief Public Health Officer, Theresa Tam, cautioned that people should aim to get the same dose in a series where possible.

“NACI is not recommending [people] just use them interchangeably, but mostly try and use the same vaccine — the mRNA [type of vaccine] — for the second dose,” Dr Tam told a media briefing.

“Try and find the same vaccine … but if you can’t for some reason, then consider them interchangeable,” she added.

The guidance is not binding but most provincial governments have indicated they were waiting for the information before setting their policies for second doses.

AP