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Disclosures: The authors report no relevant financial disclosures.
January 06, 2021
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Cases of anaphylaxis rare among first 1.9 million COVID-19 vaccinations

Disclosures: The authors report no relevant financial disclosures.
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As of Dec. 23, there were 21 confirmed cases of anaphylaxis among the first 1,893,360 recipients of the Pfizer/BioNTech COVID-19 vaccine in the United States, the CDC and FDA reported in MMWR.

This amounts to a rate of 11.1 cases of anaphylaxis per 1 million doses of COVID-19 vaccine, compared with 1.3 cases that occur per 1 million influenza vaccinations, said Nancy E. Messonnier, MD, director of the CDC’s National Center for Immunization and Respiratory Diseases.

COVID vaccine
The rate of anaphylaxis among those vaccinated with the Pfizer-BioNTech COVID-19 vaccine is 13.1 per 1 million doses.
Credit: Adobe Stock

“This may seem high, but this is still a rare outcome,” Messonnier said during a press briefing on Wednesday.

“We know that safety is one of the public’s biggest concerns about COVID-19 vaccines,” Messonnier said. “Safety was paramount throughout the development process, and the continued safety of these vaccines as they are administered to the public is of the utmost importance to the federal government. Ensuring public knowledge and confidence in the safety of these vaccines both initially and during extended use is an essential part of our national vaccine effort.”

Nancy E. Messonnier

According to the report, more than 4,000 adverse events have been observed following vaccination with Pfizer and BioNTech’s messenger RNA-based COVID-19 vaccine. Of these, 21 were confirmed cases of anaphylaxis. The report outlined that those who experienced anaphylaxis were a median 40 years of age, experienced symptoms around 13 minutes after vaccination, and had a history of allergies whether they be to food, medications or insects. According to Messonnier, no clustering was observed and patients with anaphylaxis varied from location and vaccine lots. Of the 20 patients with available follow-up data, all had recovered or had been discharged home.

Following the emergence of these data, the CDC issued updated interim clinical considerations for use of vaccines currently authorized in the U.S. and interim considerations for preparing for the potential management of anaphylaxis. According to the study, in addition to screening for contraindications and precautions before administering COVID-19 vaccines, vaccine locations should have the necessary supplies available to manage anaphylaxis, should implement postvaccination observation periods and should immediately treat persons experiencing anaphylaxis signs and symptoms with intramuscular injection of epinephrine.

Messonnier said some adverse events are coincidental and may not be related to the actual vaccine.

“I know I look forward to the day that I get to roll up my sleeve and get vaccinated,” she said.

References:

Press Conference