A CDC/MMWR study that made the news back in January found that:

The CDC said there were 21 cases of anaphylaxis — a severe and life-threatening allergic reaction that occurs rarely after vaccination — out of the nearly 1.9 million people who received their first shot of Pfizer’s Covid-19 vaccine in mid- to late December, according to a study published in the CDC’s Morbidity and Mortality Weekly Report on Wednesday.

That would mean roughly 11 people out of every million vaccinated would likely experience anaphylaxis, according to CDC data — roughly 10 times higher than the rate for the flu vaccine. [...]

Of the 21 people who experienced the severe allergic reactions [after the Covid-19 vaccine], 17 of them had a documented history of allergies or allergic reactions. Seven of those people had a history of anaphylaxis, the study found.

Has this rate of anaphylaxis reports been sustained in later months' data on the Pfizer vaccine?

(It makes some sense to ask in view of the Weber effect, which is the observation that adverse events reports [relative to treatment administrations] sometimes decrease after an initial period of heightened vigilance.)

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