As more Americans continue to get vaccinated against COVID-19, U.S. officials continue to monitor for severe allergic reactions and other adverse events after getting the vaccine.
The Centers for Disease Control and Prevention said early safety monitoring has detected 21 cases of anaphylaxis, a severe allergic reaction, after receiving the Pfizer-BioNTech COVID-19 vaccine.
The cases were detected in a pool of 1,893,360 first doses administered from Dec. 14 to 23. This translates to 11.1 cases of anaphylaxis per 1 million doses, said Dr. Nancy Messonnier, director of the CDC’s National Center for Immunization and Respiratory Diseases, in a media briefing Wednesday.
This is higher than the flu vaccine, which has an average outcome rate of 1.3 cases per 1 million doses. However, Messonnier said the rate of anaphylaxis in the COVID-19 vaccine is still considered a rare outcome.
“We all would hope that any vaccine would have zero adverse events, but even at 11 cases per million doses administered – it’s a very safe vaccine,” she said.
In 86% of the cases, symptoms began within 30 minutes of vaccination, and 81% of them occurred in people with a history of allergies or allergic reactions, including anaphylaxis events. Most of the patients who reported having this severe allergic reaction – 90% – were women.
Dr. Thomas Clark, an epidemiologist at the CDC, said 19 patients used epinephrine, a medication used to treat severe allergic reactions in an emergency situation, and all of the patients whose information was available recovered.
A total of 29 cases were reported as of Wednesday and included some patients who received the Moderna vaccine, Clark said. The agency is still investigating these cases and plans to include them in a future report.
According to the CDC, about 17 million doses of COVID-19 vaccine have shipped throughout the country, shy of the 20 million federal officials promised to be distributed by the end of 2020. As of Wednesday, 4.8 million people have been vaccinated.
Anaphylaxis is a serious, life-threatening allergic reaction and requires immediate medical attention, according to the American Academy of Allergy Asthma & Immunology. Symptoms can include skin rash, nausea, vomiting, difficulty breathing and shock. The most common anaphylactic reactions are to foods, insect stings, medication and latex.
The CDC said it will continue to monitor for adverse events, including anaphylaxis, and will regularly assess the benefits and risks of vaccination. However, the COVID-19 vaccine continues to be “an important tool in efforts to control the pandemic.”
“We’re in the setting of 2,000 COVID deaths per day,” Messonnier said. “It’s still a good value proposition to get someone vaccinated. Their risk from COVID and poor outcomes from COVID is still more than the risk of a severe outcome from the vaccine.”
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This article originally appeared on USA TODAY: COVID vaccine: CDC reports severe allergic reactions, anaphylaxis