CDC: Severe allergic reaction to COVID-19 vaccines ‘a rare event’, vast majority impacted are women

Coronavirus

Austin (KXAN) — CDC reports tracking allergic reactions to the two COVID-19 vaccines approved in the U.S. show allergic reactions happen just a fraction of the time when patients are administered either vaccine.

Overall, patients appear to respond better to the Moderna vaccine, with 2.5 anaphylaxis cases reported per million doses administered.

A report on the Pfizer-BioNTech vaccine found that rate jumps to 11.1 cases reported per million doses administered.

Moderna Vaccine

The CDC report tracking allergic reactions to Moderna’s COVID-19 vaccine found “adverse” events in reaction to the vaccine were reported just .03% of the time.

Of the 4,041,396 people given first doses of the Moderna COVID-19 vaccine as of January 20, 1,266 reported a reaction to the Vaccine Adverse Event Reporting System. 

Of those initial reports, 108 were identified for further review as possible cases of a severe allergic reaction. Only 10 were determined to be anaphylaxis, which is a severe, potentially life-threatening reaction. 

Nine of those cases were in people with a previous history of allergies or allergic reactions, and five were in people with a history of anaphylaxis.

The median interval from a patient receiving the vaccine to when they first started showing symptoms was seven and a half minutes. 

Six of the patients were hospitalized, four received treatment in an emergency department. No deaths occurred. All of these patients were women. 

An additional 47 cases were determined to be nonanaphylaxis allergic reactions, and another 47 cases were considered “nonallergic adverse events.” Investigators were unable to obtain enough information to make a determination on four reports.

In the cases involving nonanaphylaxis allergic reactions, 91% of the patients were women. 

Pfizer – BioNTech COVID-19 Vaccine

Early research on the Pfizer – BioNTech COVID-19 vaccine shows a higher percentage of patients experiencing an “adverse event” when compared to the Moderna vaccine, according to the CDC.

Of the 1,893,360 doses administered as of December 23, 2020, 4,393 (.2%) reported a reaction to the Vaccine Adverse Event Reporting System.

Of these initial reports, 175 were identified for further review as possible cases of a severe allergic reaction. 

The review determined 21 cases were anaphylaxis.

Seventeen of the patients had a documented history of allergies or allergic reactions, including seven in people with a history of anaphylaxis.

Four of the patients were hospitalized, and 17 were treated at an emergency department. No death occurred. Nineteen of the cases occurred in women. 

An additional 86 cases were determined to be nonanaphylaxis allergic reactions, and another 61 cases were considered “nonallergic adverse events.” Seven cases are still under investigation.

In the cases involving nonanaphylaxis allergic reactions, 90% of the patients were women. 

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