Anaphylactic reactions to the first dose of the Pfizer-BioNTech COVID-19 vaccine are rare, usually occur within 30 minutes of administration, and are readily treatable.

From December 14-23, 2020, following administration of 1,893,360 doses of vaccine, the CDC identified 21 case reports meeting criteria for anaphylaxis (estimated rate, 11.1 cases per million doses). Four patients (19%) were hospitalized, including three in intensive care, and 17 (81%) were treated in an emergency department.

At the time of reporting, 20 patients (95%) were known to have recovered or been discharged, and no deaths were reported. Median interval from vaccine receipt to symptom onset was 13 minutes (range, 2-150 minutes), with 71% of events occurring within 15 minutes and 86% within 30 minutes.

Data were obtained from the Vaccine Adverse Event Reporting System (VAERS), the national passive surveillance (spontaneous reporting) program. Physicians at the Centers for Disease Control and Prevention (CDC) evaluated all suspected allergic reaction events following receipt of the first dose of the Pfizer-BioNTech COVID-19 vaccine and classified them as anaphylaxis and non-anaphylaxis.

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