THURSDAY, Jan. 7, 2021 (HealthDay News) -- As of Dec. 23, 2020, researchers determined there were 21 cases of anaphylaxis (11.1 per million doses administered) after receipt of the first dose of the Pfizer-BioNTech COVID-19 vaccine in the United States, according to research published in the Jan. 6 early-release issue of the U.S. Centers for Disease Control and Prevention Morbidity and Mortality Weekly Report.
Researchers from the CDC COVID-19 Response Team and the U.S. Food and Drug Administration examined allergic reactions, including anaphylaxis, after receipt of the first dose of the Pfizer-BioNTech COVID-19 vaccine from Dec. 14 to 23, 2020.
The researchers note that as of Dec. 23, 2020, 1,893,360 first doses of the Pfizer-BioNTech COVID-19 vaccine had been administered in the United States, and there were reports of 4,393 (0.2 percent) adverse events submitted to the Vaccine Adverse Event Reporting System (VAERS). One hundred seventy-five of these events were identified as possible cases of severe allergic reaction, including anaphylaxis. Overall, 21 cases were determined to be anaphylaxis (11.1 per million doses administered), including 17 in individuals with a documented history of allergies or allergic reactions, of whom seven had a history of anaphylaxis. From vaccine receipt to symptom onset, there was a median interval of 13 minutes. All 20 persons with follow-up information had recovered or been discharged home.
"Health care providers can play an important role in vaccine safety by being vigilant in recognizing and reporting adverse events after immunization to VAERS," the authors write.