The public first began to hear about
allergic reactions to the vaccine in early December, when a health care worker
in Alaska suffered one. Later in the month, a health worker in Hamilton, Ont., went public about
her severe reaction.
On Dec. 12, Health Canada issued a
safety alert warning, saying that people with allergies to any of the ingredients in the Pfizer-BioNTech COVID-19 vaccine should not receive it.
Health Canada has been
tracking reported side-effects following COVID-19 vaccinations since early January. It notes that serious side-effects such as allergic reactions are rare, and says the benefits of the approved vaccines continue to outweigh the risks.
Up to March 19, 2021, Health Canada said there had been 2,530 reports of side-effects after COVID-19 vaccinations — that's just under 68 reports per 100,000 doses administered. Of those side-effects, 320 were considered serious.
Slightly more of those adverse effects (1,444 with 263 serious ones) were reported from the Pfizer-BioNTech vaccine than from Moderna (1,079 with 54 serious). The Covishield vaccine (the Serum Institute of India's version of AstraZeneca) had five total reported adverse effects, one of which was serious.
The most frequently reported serious adverse event was anaphylaxis, which happened in 59 cases, Health Canada said. There have been 24 post-vaccine deaths reported; 13 of them have been deemed unrelated to a vaccine, while 11 remain under investigation.