Reports of anaphylaxis after Pfizer, Moderna vaccines

Editor's Note

Since emergency use authorization of the Pfizer-BioNTech and Moderna vaccines in December, the Centers for Disease Control and Prevention’s Vaccine Adverse Event Reporting System (VAERS) has received reports of allergic reactions including anaphylaxis.

From December 14, 2020, through January 18, 2021, 9,943,247 doses of the Pfizer vaccine and 7,581,429 doses of the Moderna vaccine were administered in the US.

During this time, VAERS received 66 reports of cases of anaphylaxis—47 following the Pfizer vaccine for a reporting rate of 4.7 cases per million doses administered, and 19 after the Moderna vaccine for a reporting rate of 2.5 cases per million doses administered.

In 61 (92%) of anaphylaxis cases, patients received epinephrine. All 66 patients were treated in healthcare settings—34 (52%) in an emergency department and 32 (48%) were hospitalized (18 in the ICU and 7 required endotracheal intubation).

Of the anaphylaxis cases, 16 of the Pfizer and 5 of the Moderna patients had prior anaphylaxis, and 36 of the Pfizer and 16 of the Moderna patients had prior allergic reactions.

No deaths from anaphylaxis have been reported.