Twenty-one cases of anaphylaxis occurred with the first 1.9 million doses of the Pfizer-BioNTech mRNA COVID-19 vaccine, according to data in MMWR. This equates to a rate of 11.1 cases per 1 million doses. In comparison, the anaphylaxis rate with influenza vaccination is 1.3 per million.
On the one hand, that’s about eight times as many anaphylaxis reactions as the flu vaccine causes, which is unfortunate. But on the other hand, it’s only slightly more likely than being struck by lightning in the next year. This is still an extremely rare thing affecting just a thousandth of a percent of vaccine recipients, most of those cases (17) were in people with a known history of strong allergic reactions… and they are all just fine.
The risk is trivial compared to the risks of getting COVID.
An interesting footnote about the speed of reactions: most anaphylaxis struck within fifteen minutes, but many took much longer, and the longest took more than two hours. This is why they ask you to stick around for a while after a vaccination! And yet, given the statistics, that may be the ultimate example of “an abundance of caution.”