Dr. Isaac Bogoch, an infectious diseases physician and member of Ontario's COVID-19 vaccine task force said that the discovery of a potential connection with the vaccine to blood clots raised a "red flag" that "warrants further exploration."
"People should appreciate that not all blood clots are created the same," he said. "This is a very specific and particular method of blood clotting that likely has an association with the vaccine."
But 18 of the cases in Europe were of an extremely rare type of blood clot called cerebral venous sinus thrombosis (CVST) — where veins that drain blood from the brain are obstructed and can potentially cause fatal bleeding.
The EMA said on March 18 at least nine deaths have been associated with the adverse events in Europe and the agency is continuing to investigate the situation.
Germany's medical regulator told The Associated Press on Monday it had received reports of 21 cases of rare blood clots in people who had recently received AstraZeneca's coronavirus vaccine.
The Paul Ehrlich Institute also said that seven people affected by the blood clots have died. It added that of the 21 cases reported in Germany until March 25, 12 also involved an abnormally low level of platelets in the patients' blood.
Canadian health officials said during a press conference Monday the specific syndrome is being called Vaccine-Induced Prothrombotic Immune Thrombocytopenia (VIPIT) and that they are in contact with European officials about it.
Officials added that Germany's Paul Ehrlich Institute reported VIPIT has an incidence rate of about one in 100,000, with a mortality rate of about 40 per cent, although more research is needed and that risk is reduced if treated early enough.