3rd wave hitting younger Canadians harder, but AstraZeneca vaccine only for 55+ due to rare blood clot risk. Canada’s decision to suspend the use of the AstraZeneca-Oxford vaccine in Canadians under 55 during a surging third wave and a slow vaccination rollout is a calculated risk. The National Advisory Committee on Immunization (NACI) updated its guidance to provinces and territories against the use of the vaccine for younger Canadians on Monday, following reports of rare but potentially fatal blood clots in Europe connected to the shot. Health Canada says the benefits of the vaccine to protect against COVID-19 still outweigh the potential risks, with more than 300,000 doses of the shot administered and no cases of the serious clotting condition, known as vaccine-induced prothrombotic immune thrombocytopenia (VIPIT), in Canada. But the decision to restrict the use of one of four approved vaccines at a time when COVID-19 levels are rising again in Canada’s hardest hit provinces is a tough pill to swallow for some.